🎯Pradeep Menon - Collected Quotes

"A data sharing data service shares data, in any format and any size, from multiple sources within an organization or other organizations. This type of service provides the required control to share data and allows data-sharing policies to be created. It also enables data sharing in a structured manner and offers complete visibility into how the data is shared and how it is used. A data-sharing system uses APIs for data sharing." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"A data lakehouse stores a lot of data. It stores data in the data lake layer and the serving layer in structured and unstructured formats. The data needs to be processed with different types of compute engines. It can be a batch-based compute or a stream-based compute. A tightly coupled compute and storage layer strips off the flexibility required in a data lakehouse. Decoupling compute and storage also has a cost implication - storage is cheap and persistent but compute is expensive and ephemeral. It gives you the flexibility to spin up compute services on-demand and scale them as required, and also gives better cost control and cost predictability." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"A data warehouse service provides cleansed and transformed data that can be used for multiple purposes. First, it serves as a layer for reporting and BI. Second, it is a platform to query data for business or data analysis. Third, it serves as a repository to store historical data that needs to be online and available. Finally, it also acts as a source of transformed data for other downstream data marts that may cater to specific departmental requirements." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"An API is an interface that allows applications to interact with an external service using a simple set of commands. Data can also be served as part of API interaction. As the data is exposed to multiple external services, API-based methods can scale to share data securely with external services. Data through an API is served in JSON format, therefore the technology used to serve the data using APIs should be able to support JSON formats. For example, a NoSQL database can store such data." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"Any change in the reporting requirement had to go through a long-winded process of data model changes, ETL code changes, and respective changes to the reporting system. Often, the ETL process was a specialized skill and became a bottleneck for reducing data to insight turnover time. The nature of analytics is unique. The more you see the output, the more you demand. Many EDW projects were deemed a failure. The failure was not from a technical perspective, but from a business perspective. Operationally, the design changes required to cater to these fast-evolving requirements were too difficult to handle." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"Data architecture is the structure that enables the storage, transformation, exploitation, and governance of data." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"The AI-ML service allows data scientists to build, train and deploy production-ready AI-ML models. This layer also provides the framework to maintain and monitor such models. In addition, it gives the ability for teams to collaborate as they go about building these models. This service should be able to scale up and down as required and should be able to facilitate automatic model deployment and operations." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"A Data Lake is a centralized repository that allows you to store all your structured and unstructured data at any scale. You can store your data as-is without having first to structure the data and run different types of analytics  - from dashboards and visualizations to big data processing, real-time analytics, and machine learning to guide better decisions." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"A Data Lakehouse provides a unified platform for various data workloads, such as descriptive, predictive, and prescriptive analytics. It can handle structured and unstructured data and enforce schema at both read and write times, enabling traditional business intelligence tasks and advanced analytics on the same platform." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"A defining attribute of the domain-oriented ownership principle is the focus on context preservation in Data Management. This aspect accentuates the importance of keeping data within its native domain environment, allowing it to retain its original context, value, and meaning. When data is managed close to its source, its contextual richness is preserved. This sharply contrasts centralized models, where data is often abstracted from its source, leading to potential loss of signal or context. When data remains within its generating domain, it retains the nuances and specificities unique to its activities, challenges, and goals." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"A transformative perspective offered by the Data Mesh is envisioning data as a product. This section underscores the significance of curating data with the meticulousness and vision akin to product development, ensuring it delivers tangible value to its consumers. The ripple effects of this paradigm shift, spanning roles, processes, and technologies, are also meticulously unpacked." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Centralized governance structures often have an abstract view of data, focusing more on uniformity and compliance than context and relevance. While these are essential elements, the nuance often needs to be noticed. Decentralized governance flips the script by giving data ownership to the domain that generates it. The domain has the richest understanding of the data’s context, relevance, and potential impact, thereby being well-positioned to enforce governance policies that improve data quality." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Data Mesh also emphasizes aligning data products with business domains and use- cases to ensure that the data serves a clear business purpose and provides tangible value. Beforehand, we define the value proposition, target audience, quality attributes, and KPIs of each data product to ensure that it meets or exceeds the expectations of its consumers." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Data Mesh emphasizes ensuring reliable, consistent, and interoperable data products. When data is treated as a product, quality is non-negotiable. High-quality data must meet the expectations and requirements of its users, both internally and externally. Additionally, data products must be designed with other products in mind, adhering to principles like loose coupling for easy interchangeability and high cohesion for strong functional relatedness. This feature enables the integration of different data products, ensuring seamless interoperability and greater usability. Data products should be reliable, complete, accurate, and accurate. They should also be integrated, compatible, and consistent rather than isolated, incompatible, or conflicting." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"[...] domain-oriented ownership empowers individual domains to create and adapt their data strategies with agility, with a thorough understanding of their business needs and market demands. Whether pivoting due to a new competitor’s actions or adjusting to a sudden change in consumer behavior, domains can independently and swiftly modify their data strategies, providing them with a unique edge in the marketplace." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Domain-oriented ownership is a core principle of data mesh. It entails that data producers, experts in their business domains, are responsible for the entire lifecycle of their produced data. Specifically, they take ownership of the data from the point of ingestion through transformation, serving, quality assurance, and governance. Moreover, they are responsible for the data products created from their data, which serve as units of data consumption for other domains or users." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Domain autonomy should not be mistaken for a lack of governance or accountability. Autonomy, in this context, implies a higher level of responsibility. Domains are free to act and accountable for their actions, especially regarding how well their data strategies align with domain-specific and broader organizational objectives." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Empowering with self-serve data infrastructure: The Data Mesh champions the ethos of self-reliance. By empowering teams to construct and oversee their data infrastructure, organizations can foster a culture of speed, autonomy, and accountability." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Governance refers to an organization’s framework to exercise direction and control over a specific domain. In the context of data, it could include rules, protocols, and systems to manage data quality, security, and accessibility."  (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"In a centralized model, changes to data strategy often require navigating through bureaucratic layers and rigid governance structures. This delays adaptability and increases the risk of misalignment between what the data strategy aims to achieve and what the business needs. Centralized models are typically disconnected from the ground realities of individual business units, leading to a generic, one-size-fits-all approach that seldom caters to unique market challenges or opportunities." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Promoting domain-oriented ownership is to combat the common problem of organizational silos. Silos can significantly hinder the free flow of data and expertise, making decision-making and innovation more challenging. We aim to break down these barriers by advocating for domain-oriented ownership and creating a more dynamic and collaborative data management landscape." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"The allure of Data Lakes was their ability to store vast amounts of raw data. However, this advantage can become counterproductive without stringent governance and management protocols. In their zeal to harness the power of Big Data, some organizations indiscriminately dump data into their lakes. Without proper classification, curation, and quality checks, these lakes can become swamps - murky repositories filled with valuable data, redundant information, and outdated datasets. Navigating these data swamps becomes a significant challenge, leading to prolonged data retrieval times, increased chances of using obsolete or incorrect data, and a decline in the agility and efficiency of data-driven decision-making processes rather than facilitating quick and insightful analytics." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"When data is considered a product, it creates opportunities for collaboration across different domains. This collaboration involves working with other teams to create, share, and use data products that span multiple areas of expertise, interest, or value. Data Mesh promotes cross-domain collaboration by focusing on the consumers rather than the producers. Data products are made available through standardized interfaces and protocols that support various modes of consumption and are governed by domain experts who understand the context and nuances of their data." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

🎯Fadi Maali - Collected Quotes

"A common mistake when implementing a data catalog is to focus only on technical metadata. This limits its use and the potential value. It also excludes business users who have valuable related input or need to use the catalog. A catalog should in fact function as a two-way translation layer between technical and business users." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"A core premise of data mesh is federating data ownership among domain data owners who are responsible for their data as a product. Offering the data as a product requires the data to be discoverable and to have explicitly stated quality characteristics and a clearly defined access method. Such requirements are at the core of what data catalogs support. With support for data labeling, curation, and crowdsourced feedback, data catalogs are well positioned to offer data as a product. Furthermore, data catalogs support the enforcement of compliant data usage, which becomes more important when data ownership is not managed centrally." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Active governance guides users as they find and use data. A data catalog with active governance will surface compliance information about sensitive data at point of use, so as to encourage users to use canonical and high-quality data assets; it will also provide a way to ask domain experts for help. They actively help users to ensure compliant usage of data with features such as masking, which anonymizes PII for given user personas who are restricted from viewing it per the GDPR." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Build a community around the catalog. Make sure data producers, stewards, and consumers are all involved and empowered to enrich the content of the catalog. Establish a leader or a team to have clear ownership of the data catalog." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Data catalog platforms take a more holistic view to focus not only on data assets within an enterprise, but also on the surrounding ecosystem (including business and people elements). They are typically characterized by an extensible data model that can grow to define various assets and concepts, such as metrics, charts, AI features, and users. Data catalog platforms typically augment their data with a focus on business and users to support collaborative governance and enrichment of metadata and to interlink data with business glossaries and dictionaries. Moreover, they are architected to make them easily integrable with other systems." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Data catalogs that focus on governance are concerned mainly with controlling data access and ensuring that data is used according to defined policies; this includes external policies such as data privacy laws as well as policies defined with an enterprise. Those catalogs apply techniques to identify data assets with sensitive information and to monitor data flow and access." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Data catalogs that focus on search bring techniques and methods from information retrieval and web search engines to the data domain within enterprises. Some of those catalogs, such as Facebook Nemo, use advanced machine learning and NLP tools to provide personalized search of data within an enterprise. The search can also use data-specific signals such as usage, popularity, and freshness to rank data assets by usefulness." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Enterprises typically become interested in data catalogs when they have a specific use case or need in mind. Data governance, self-service analytics, and cloud data migration are common examples. Having a specific need or use case helps focus efforts and measure impact. However, as with other technical efforts within enterprises, it is essential to prepare for long-term sustainable success and to have a plan to maximize successful adoption." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Historically, for their analytics needs, enterprises relied upon a set of tightly coupled tools, typically provided by a single vendor. Nowadays, nearly all of the components of a traditional data warehouse are independent and interchangeable. Those independent tools can be flexibly combined to provide a modern data stack. It is common for current enterprises to have separate tools for data ingestion, data pipelines, data storage and querying, data visualization and business intelligence, and data quality. Furthermore, data can flow in the opposite direction out of the data warehouse in what is referred to as reverse extract, transform, and load (ETL)." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"In a self-service environment with multiple publishers, it’s impossible to completely avoid data redundancy and overlapping. Multiple data assets with similar content, but possibly with varying quality, will exist. A data catalog can guide users to trusted data that comes from a reliable source and is frequently used. A data catalog can also use various explicit and implicit quality signals when ranking datasets for recommendation. Some of those signals are discussed next. Furthermore, a data catalog can recommend domain experts who are automatically identified based on actual data usage." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"It is often said that data scientists and data analysts spend only 20% of their time doing data analysis work, with 80% consumed by data 'issues'. The bulk of their time is spent finding, evaluating, understanding, and preparing data before analysis can begin. A data catalog inverts this principle by enabling data analysts and data scientists to spend 20% of their time looking for data and 80% performing analysis." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Self-service BI initiatives help organizations become more data-driven and democratize access to data. But data can’t be used if it can’t be found. Search and discovery of trustworthy data is a core value of enterprise data catalogs, and the value extends well beyond business users." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

🪙Business Intelligence: Data Storage (Just the Quotes)

"A data lake is a storage repository that holds a very large amount of data, often from diverse sources, in native format until needed. In some respects, a data lake can be compared to a staging area of a data warehouse, but there are key differences. Just like a staging area, a data lake is a conglomeration point for raw data from diverse sources. However, a staging area only stores new data needed for addition to the data warehouse and is a transient data store. In contrast, a data lake typically stores all possible data that might be needed for an undefined amount of analysis and reporting, allowing analysts to explore new data relationships. In addition, a data lake is usually built on commodity hardware and software such as Hadoop, whereas traditional staging areas typically reside in structured databases that require specialized servers." (Mike Fleckenstein & Lorraine Fellows, "Modern Data Strategy", 2018)

"Data swamp, on the other hand, presents the devil side of a lake. A data lake in a state of anarchy is nothing but turns into a data swamp. It lacks stable data governance practices, lacks metadata management, and plays weak on ingestion framework. Uncontrolled and untracked access to source data may produce duplicate copies of data and impose pressure on storage systems." (Saurabh Gupta et al, "Practical Enterprise Data Lake Insights", 2018)

"A data lakehouse is an amalgamation of the best components from both data lakes and data warehouses. A data lakehouse implements data structure and data management features from data warehouses into a cost-effective storage like a data lake. It tries to combine the best from both worlds - data lake - based Big Data analytics and a data warehouse." (Bhadresh Shiyal, "Beginning Azure Synapse Analytics: Transition from Data Warehouse to Data Lakehouse", 2021) 

"Data fabrics are general-purpose, organization-wide data access interfaces that offer a connected view of the integrated domains by combining data stored in a local graph with data retrieved on demand from third-party systems. Their job is to provide a sophisticated index and integration points so that they can curate data across silos, offering consistent capabilities regardless of the underlying store (which might or might not be graph based) […]." (Jesús Barrasa et al, "Knowledge Graphs: Data in Context for Responsive Businesses", 2021)

"Data architecture is the structure that enables the storage, transformation, exploitation, and governance of data." (Pradeep Menon, "Data Lakehouse in Action", 2022)

"Data mesh relies on a distributed architecture that consists of domains. Each domain is an independent unit of data and its associated storage and compute components. When an organization contains various product units, each with its own data needs, each product team owns a domain that is operated and governed independently by the product team. […] Data mesh has a unique value proposition, not just offering scale of infrastructure and scenarios but also helping shift the organization’s culture around data," (Rukmani Gopalan, "The Cloud Data Lake: A Guide to Building Robust Cloud Data Architecture", 2022)

"Historically, for their analytics needs, enterprises relied upon a set of tightly coupled tools, typically provided by a single vendor. Nowadays, nearly all of the components of a traditional data warehouse are independent and interchangeable. Those independent tools can be flexibly combined to provide a modern data stack. It is common for current enterprises to have separate tools for data ingestion, data pipelines, data storage and querying, data visualization and business intelligence, and data quality. Furthermore, data can flow in the opposite direction out of the data warehouse in what is referred to as reverse extract, transform, and load (ETL)." (Fadi Maali & Jason Lim, "Implementing a Modern Data Catalog to Power Data Intelligence: Make Trustworthy Data Central to Your Organization", 2022)

"Lakehouse is a new architecture and data storage paradigm that combines the characteristics of both data warehouses and data lakes to create a unified basis for all types of use cases to be built on top of it. There is no need to move data around. Data is curated and remains in an open format and serves as the single source of truth (SSOT) for all the consumption layers. A modern data platform has needs that span traditional data warehouses, data lakes, machine learning systems, and streaming systems and there is some overlap among these systems. A Lakehouse offers features that span all four systems [...]" (Anindita Mahapatra, "Simplifying Data Engineering and Analytics with Delta", 2022)

"The lakehouse provides a key advantage over the modern data warehouse by eliminating the need to have two places to store the same data." (Rukmani Gopalan, "The Cloud Data Lake: A Guide to Building Robust Cloud Data Architecture", 2022)

"When it comes to data lakes, some things usually stay constant: the storage and processing patterns. Change could come in any of the following ways: Adding new components and processing or consumption patterns to respond to new requirements. […] Optimizing existing architecture for better cost or performance" (Rukmani Gopalan, "The Cloud Data Lake: A Guide to Building Robust Cloud Data Architecture", 2022)

"A Data Lake is a centralized repository that allows you to store all your structured and unstructured data at any scale. You can store your data as-is without having first to structure the data and run different types of analytics  - from dashboards and visualizations to big data processing, real-time analytics, and machine learning to guide better decisions." (Pradeep Menon, "Data Mesh Principles, patterns, architecture, and strategies for data-driven decision making", 2024)

"Delta Lake is a transactional storage software layer that runs on top of an existing data lake and adds RDW-like features that improve the lake’s reliability, security, and performance. Delta Lake itself is not storage. In most cases, it’s easy to turn a data lake into a Delta Lake; all you need to do is specify, when you are storing data to your data lake, that you want to save it in Delta Lake format (as opposed to other formats, like CSV or JSON)." (James Serra, "Deciphering Data Architectures", 2024)

"Federation is about providing autonomy to each data product owner to make their own decisions about the storage, computing, and sharing of data. However, this autonomy cannot come at a risk to the security and compliance standards of the company." (Aniruddha Deswandikar, "Engineering Data Mesh in Azure Cloud", 2024)

"Observability [...] requires that systems be instrumented to expose rich telemetry, enabling ad hoc exploration and hypothesis testing regarding system health. Thus, observability demands design considerations at the architecture level, insisting on standardization of instrumentation, consistent metadata management, and tight integration across data processing, storage, and orchestration layers." (William Smith, "Soda Core for Modern Data Quality and Observability: The Complete Guide for Developers and Engineers", 2025)

"Data virtualization is a technique that allows users and applications to access and interact with data stored in multiple, physically separate locations as if it were all in one place. Instead of moving or duplicating data, virtualization creates a logical layer that connects to the original sources and presents them in a unified view. This means users can query, analyze, or combine data from different systems - cloud storage, databases, or other platforms - without needing to know where or how the data is stored." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Fabric integrates the various technologies needed for an end-to-end data project (namely, ingestion, preparation, storage, processing, enrichment, analysis, visualization, and data sharing) within a single platform accessible as Software as a Service (SaaS), meaning via a simple connection on a web browser. This reduces complexity, costs, and delays related to using multiple tools and technologies, and eliminates all the operational maintenance of infrastructure serving data analytics needs." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Fabric relies on a lakehouse, a data storage model that combines the benefits of a data lake and a data warehouse. Within Fabric, the various data analytics and processing tools rely on a data lake that collects and stores data in its original format, whether structured, semi-structured, or unstructured, without the need to transform or normalize it beforehand. The lakehouse approach then enables converting these diverse data formats into a single format (i.e., compatible with all the data processing engines offered by Fabric) and in an open format, allowing other market vendors to interact with data in the Fabric lakehouse." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

🪙Business Intelligence: Problems (Just the Quotes)

"Charts and graphs are a method of organizing information for a unique purpose. The purpose may be to inform, to persuade, to obtain a clear understanding of certain facts, or to focus information and attention on a particular problem. The information contained in charts and graphs must, obviously, be relevant to the purpose. For decision-making purposes. information must be focused clearly on the issue or issues requiring attention. The need is not simply for 'information', but for structured information, clearly presented and narrowed to fit a distinctive decision-making context. An advantage of having a 'formula' or 'model' appropriate to a given situation is that the formula indicates what kind of information is needed to obtain a solution or answer to a specific problem." (Cecil H Meyers, "Handbook of Basic Graphs: A modern approach", 1970)

"Unfortunately, just collecting the data in one place and making it easily available isn’t enough. When operational data from transactions is loaded into the data warehouse, it often contains missing or inaccurate data. How good or bad the data is a function of the amount of input checking done in the application that generates the transaction. Unfortunately, many deployed applications are less than stellar when it comes to validating the inputs. To overcome this problem, the operational data must go through a 'cleansing' process, which takes care of missing or out-of-range values. If this cleansing step is not done before the data is loaded into the data warehouse, it will have to be performed repeatedly whenever that data is used in a data mining operation." (Joseph P Bigus,"Data Mining with Neural Networks: Solving business problems from application development to decision support", 1996)

"Changing measures are a particularly common problem with comparisons over time, but measures also can cause problems of their own. [...] We cannot talk about change without making comparisons over time. We cannot avoid such comparisons, nor should we want to. However, there are several basic problems that can affect statistics about change. It is important to consider the problems posed by changing - and sometimes unchanging - measures, and it is also important to recognize the limits of predictions. Claims about change deserve critical inspection; we need to ask ourselves whether apples are being compared to apples - or to very different objects." (Joel Best, "Damned Lies and Statistics: Untangling Numbers from the Media, Politicians, and Activists", 2001)

"[...] a good definition of a data product is a product that facilitates an end goal through the use of data. It’s tempting to think of a data product purely as a data problem. After all, there’s nothing more fun than throwing a lot of technical expertise and fancy algorithmic work at a difficult problem." (Dhanurjay Patil, "Data Jujitsu: The Art of Turning Data into Product", 2012)

"Metrics can serve two purposes: identifying problems and measuring performance. When the goal is to identify problems and pinpoint areas of operational inefficiency and ineffectiveness, defining the right metric requires a bit of detective work. It requires you to uncover the data residue of a problem and to determine what evidence can be found and how exactly it shows up. When the goal is to measure performance, the right success metrics focus on measures that can be controlled and where improvement in the metric is an unambiguously good thing." (Zach Gemignani et al, "Data Fluency", 2014)

"Data mart: A subset of a data warehouse that’s usually oriented to a business group or process rather than enterprise-wide views. They have value as part of the overall enterprise data architecture, but can cause problems when they sprout uncontrolled as data silos with their own data definitions, creating data shadow systems." (Rick Sherman, "Business Intelligence Guidebook: From Data Integration to Analytics, 2015)

"Having multiple data lakes replicates the same problems that were created with multiple data warehouses - disparate data siloes and data fiefdoms that don't facilitate sharing of the corporate data assets across the organization. Organizations need to have a single data lake from which they can source the data for their BI/data warehousing and analytic needs. The data lake may never become the 'single version of the truth' for the organization, but then again, neither will the data warehouse. Instead, the data lake becomes the 'single or central repository for all the organization's data' from which all the organization's reporting and analytic needs are sourced." (Billl Schmarzo, "Driving Business Strategies with Data Science: Big Data MBA" 1st Ed., 2015)

"There are, however, many problems with independent data marts. Independent data marts: (1) Do not have data that can be reconciled with other data marts (2) Require their own independent integration of raw data (3) Do not provide a foundation that can be built on whenever there are future analytical needs." (William H Inmon & Daniel Linstedt, "Data Architecture: A Primer for the Data Scientist: Big Data, Data Warehouse and Data Vault", 2015)

"Data warehousing, as we are aware, is the traditional approach of consolidating data from multiple source systems and combining into one store that would serve as the source for analytical and business intelligence reporting. The concept of data warehousing resolved the problems of data heterogeneity and low-level integration. In terms of objectives, a data lake is no different from a data warehouse. Both are primary advocates of terms like 'single source of truth' and 'central data repository'." (Saurabh Gupta et al, "Practical Enterprise Data Lake Insights", 2018)

"Data has historically been treated as a second-class citizen, as a form of exhaust or by-product emitted by business applications. This application-first thinking remains the major source of problems in today’s computing environments, leading to ad hoc data pipelines, cobbled together data access mechanisms, and inconsistent sources of similar-yet-different truths. Data mesh addresses these shortcomings head-on, by fundamentally altering the relationships we have with our data. Instead of a secondary by-product, data, and the access to it, is promoted to a first-class citizen on par with any other business service." (Adam Bellemare,"Building an Event-Driven Data Mesh: Patterns for Designing and Building Event-Driven Architectures", 2023)

"With all the hype, you would think building a data mesh is the answer to all of these 'problems' with data warehousing. The truth is that while data warehouse projects do fail, it is rarely because they can’t scale enough to handle big data or because the architecture or the technology isn’t capable. Failure is almost always because of problems with the people and/or the process, or that the organization chose the completely wrong technology." (James Serra, "Deciphering Data Architectures", 2024)

🔭Data Science: Standards (Just the Quotes)

"At the present time there is a total lack of standardization in the form of diagram to use for nearly all classes of representation. This makes it difficult to compare reports of different investigators on the same subject because their diagrams are not constructed alike." (William C Marshall,Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)

"Precision is expressed by an international standard, viz., the standard error. It measures the average of the difference between a complete coverage and a long series of estimates formed from samples drawn from this complete coverage by a particular procedure or drawing, and processed by a particular estimating formula." (W Edwards Deming,On the Presentation of the Results of Sample Surveys as Legal Evidence", Journal of the American Statistical Association Vol 49 (268), 1954)

"The relevant question is not whether ANOVA assumptions are met exactly, but rather whether the plausible violations of the assumptions have serious consequences on the validity of probability statements based on the standard assumptions." (Gene V Glass et al,Consequences of Failure to Meet Assumptions Underlying the Fixed Effects Analyses of Variance and Covariance", Review of Educational Research Vol. 42 (3), 1972)

"Exploratory data analysis, EDA, calls for a relatively free hand in exploring the data, together with dual obligations: (•) to look for all plausible alternatives and oddities - and a few implausible ones, (graphic techniques can be most helpful here) and (•) to remove each appearance that seems large enough to be meaningful - ordinarily by some form of fitting, adjustment, or standardization [...] so that what remains, the residuals, can be examined for further appearances." (John W Tukey,Introduction to Styles of Data Analysis Techniques", 1982)

"The conditions under which many data graphics are produced - the lack of substantive and quantitative skills of the illustrators, dislike of quantitative evidence, and contempt for the intelligence of the audience-guarantee graphic mediocrity. These conditions engender graphics that (1) lie; (2) employ only the simplest designs, often unstandardized time-series based on a small handful of data points; and (3) miss the real news actually in the data." (Edward R Tufte,The Visual Display of Quantitative Information", 1983)

"It would help if the standard statistical programs did not generate t statistics in such profusion. The programs might be written to ask, 'Do you really have a probability sample?', 'By what standard would you judge a fitted coefficient large or small?' Or perhaps they could merely say, printed in bold capitals beside each equation, 'So What Else Is New?'" (Donald M McCloskey,The Loss Function Has Been Mislaid: The Rhetoric of Significance Tests", American Economic Review Vol. 75, 1985)

"When evaluating a model, at least two broad standards are relevant. One is whether the model is consistent with the data. The other is whether the model is consistent with the ‘real world.’" (Kenneth Bollen,Structural Equations with Latent Variable", 1989)

"With each pattern, small piecework is standardized into a larger chunk or unit. Patterns become the building blocks for design and construction. Finding and applying patterns indicates progress in a field of human endeavor." (Peter Coad,Object-Oriented Pattern", 1992)

"One important aspect of reality is improvisation; as a result of special structure in a set of data, or the finding of a visualization method, we stray from the standard methods for the data type to exploit the structure or the finding." (William S Cleveland,Visualizing Data", 1993)

"When the distributions of two or more groups of univariate data are skewed, it is common to have the spread increase monotonically with location. This behavior is monotone spread. Strictly speaking, monotone spread includes the case where the spread decreases monotonically with location, but such a decrease is much less common for raw data. Monotone spread, as with skewness, adds to the difficulty of data analysis. For example, it means that we cannot fit just location estimates to produce homogeneous residuals; we must fit spread estimates as well. Furthermore, the distributions cannot be compared by a number of standard methods of probabilistic inference that are based on an assumption of equal spreads; the standard t-test is one example. Fortunately, remedies for skewness can cure monotone spread as well." (William S Cleveland,Visualizing Data", 1993)

"While some social problems statistics are deliberate deceptions, many - probably the great majority - of bad statistics are the result of confusion, incompetence, innumeracy, or selective, self-righteous efforts to produce numbers that reaffirm principles and interests that their advocates consider just and right. The best response to stat wars is not to try and guess who's lying or, worse, simply to assume that the people we disagree with are the ones telling lies. Rather, we need to watch for the standard causes of bad statistics - guessing, questionable definitions or methods, mutant numbers, and inappropriate comparisons." (Joel Best,Damned Lies and Statistics: Untangling Numbers from the Media, Politicians, and Activists", 2001)

"The definition of a ‘good model’ is when everything inside it is visible, inspectable and testable. It can be communicated effortlessly to others. A ‘bad model’ is a model that does not meet these standards, where parts are hidden, undefined or concealed and it cannot be inspected or tested; these are often labelled black box models." (Hördur V Haraldsson & Harald U Sverdrup,Finding Simplicity in Complexity in Biogeochemical Modelling" [inEnvironmental Modelling: Finding Simplicity in Complexity", Ed. by John Wainwright and Mark Mulligan, 2004])

"The inevitability of variability complicates the evaluation and use of data. It must be recognized that many uses require data quality that may be difficult to achieve. There are minimum quality standards required for every measurement situation (sometimes called data quality objectives). These standards should be established in advance and both the producer and the user must be able to determine whether they have been met. The only way that this can be accomplished is to attain statistical control of the measurement process and to apply valid statistical procedures in the analysis of the data." (Cheryl Cihon & John K Taylor, "Statistical Techniques for Data Analysis" 2nd. ed., 2005)

"Regularization works because it is the sum of the coefficients of the predictor variables, therefore it’s important that they’re on the same scale or the regularization may find it difficult to converge, and variables with larger absolute coefficient values will greatly influence it, generating an infective regularization. It’s good practice to standardize the predictor values or bind them to a common min‐max, such as the [‐1,+1] range." (Luca Massaron & John P Mueller,Python for Data Science For Dummies", 2015)

"The closer that sample-selection procedures approach the gold standard of random selection - for which the definition is that every individual in the population has an equal chance of appearing in the sample - the more we should trust them. If we don’t know whether a sample is random, any statistical measure we conduct may be biased in some unknown way." (Richard E Nisbett,Mindware: Tools for Smart Thinking", 2015)

"Measurements must be standardized. There must be clear, replicable, and precise procedures for collecting data so that each person who collects it does it in the same way." (Daniel J Levitin,Weaponized Lies", 2017)

"The danger of overfitting is particularly severe when the training data is not a perfect gold standard. Human class annotations are often subjective and inconsistent, leading boosting to amplify the noise at the expense of the signal. The best boosting algorithms will deal with overfitting though regularization. The goal will be to minimize the number of non-zero coefficients, and avoid large coefficients that place too much faith in any one classifier in the ensemble." (Steven S Skiena,The Data Science Design Manual", 2017)

"There is often no one 'best' visualization, because it depends on context, what your audience already knows, how numerate or scientifically trained they are, what formats and conventions are regarded as standard in the particular field you’re working in, the medium you can use, and so on. It’s also partly scientific and partly artistic, so you get to express your own design style in it, which is what makes it so fascinating." (Robert Grant,Data Visualization: Charts, Maps and Interactive Graphics", 2019) 

📉Graphical Representation: Speed (Just the Quotes)

"Since a table is a collection of certain sets of data, a chart with one curve representing each set of data can be made to take the place of the table. Wherever a chart can be plotted by straight lines, the speed of this is infinitely greater than making out a table, and where the curvilinear law is known, or can be approximated by the use of the empiric law, the speed is but little less." (Allan C Haskell, "How to Make and Use Graphic Charts", 1919)

"For many purposes graphical accuracy is sufficient. The speed of graphical processes, and more especially the advantages of visual presentation in pointing out facts or clues which might otherwise be overlooked, make graphical analysis very valuable." (Frederick Mosteller & John W Tukey, "The Uses and Usefulness of Binomial Probability Paper?", Journal of the American Statistical Association 44, 1949)

"Since the chief purpose of the nomogram is to make exact data available for operational use, its chief competitor is the table. Operational tables may break Ehrenberg's two-digit rule, since they are not used to detect general trends but to provide exact data for some operational purpose. The choice  between nomogram and table involves a complex tradeoff among cost, space, convenience, accuracy, and speed. These tradeoff situations provide one good reason why no one graphic format is suitable for all purposes. Of course, there can be good methods (sarisfying solutions) for particular cases." (Michael Macdonald-Ross, "Graphics in Texts", Review of Research in Education Vol. 5, 1977)

"The ease and speed with which tables can be understood depends very much on the tabulation logic. The author must ask himself what information the reader already has when he consults a particular table, and what information he is seeking from it. The row and column headings should relate to the information he already has, thus leading him to the information he seeks which is displayed in the body of the table." (Linda Reynolds & Doig Simmonds, "Presentation of Data in Science" 4th Ed, 1984)

"There are some who argue that a graph is a success only if the important information in the data can be seen within a few seconds. While there is a place for rapidly-understood graphs, it is too limiting to make speed a requirement in science and technology, where the use of graphs ranges from, detailed, in-depth data analysis to quick presentation." (William S Cleveland, "The Elements of Graphing Data", 1985)

"Working with binned data directly addresses large data set issues of computation and plotting speed. Almost everything that can bc done with the original data can be done faster with binned data. Further, working with binned data allows image processing algorithms to be adapted and applied to bin cells. Thus tools can bc brought to bare that are not traditionally associated with exploratory data analysis." (Daniel B Carr, "Looking at Large Data Sets Using Binned Data Plots", [in "Computing and Graphics in Statistics"] 1991)

"In general. statistical graphics should be moderately greater in length than in height. And, as William Cleveland discovered, for judging slopes and velocities up and down the hills in time-series, best is an aspect ratio that yields hill - slopes averaging 45°, over every cycle in the time-series. Variations in slopes are best detected when the slopes are around 45°, uphill or downhill." (Edward R Tufte, "Beautiful Evidence", 2006)

"Sparklines are wordlike graphics, With an intensity of visual distinctions comparable to words and letters. [...] Words visually present both an overall shape and letter-by-letter detail; since most readers have seen the word previously, the visual task is usually one of quick recognition. Sparklines present an overall shape and aggregate pattern along with plenty of local detail. Sparklines are read the same way as words, although much more carefully and slowly." (Edward R Tufte, "Beautiful Evidence", 2006)

"The biggest difference between line graphs and sparklines is that a sparkline is compact with no grid lines. It isnʼt meant to give precise values; rather, it should be considered just like any other word in the sentence. Its general shape acts as another term and lends additional meaning in its context. The driving forces behind these compact sparklines are speed and convenience." (Brian Suda, "A Practical Guide to Designing with Data", 2010)

"As a first principle, any visualization should convey its information quickly and easily, and with minimal scope for misunderstanding. Unnecessary visual clutter makes more work for the reader’s brain to do, slows down the understanding" (at which point they may give up) and may even allow some incorrect interpretations to creep in." (Robert Grant, "Data Visualization: Charts, Maps and Interactive Graphics", 2019)

"The way we explore data today, we often aren't constrained by rigid hypothesis testing or statistical rigor that can slow down the process to a crawl. But we need to be careful with this rapid pace of exploration, too. Modern business intelligence and analytics tools allow us to do so much with data so quickly that it can be easy to fall into a pitfall by creating a chart that misleads us in the early stages of the process." (Ben Jones, "Avoiding Data Pitfalls: How to Steer Clear of Common Blunders When Working with Data and Presenting Analysis and Visualizations", 2020)

🎯Christopher Maneu - Collected Quotes

"A data lake is a distributed repository of raw and unprocessed data stored in its original format, without a predefined schema or structure. A data lake is designed to support a wide range of data types, sources, and use cases, such as exploration, discovery, and data experimentation. A data lake follows a 'schema on read' approach. Data is structured and processed only when it is accessed or consumed by a user or application (Extract, Load, Transform (ELT)). A data lake also enables data democratization, meaning data is accessible and available to anyone who needs it, without barriers or restrictions." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"A data warehouse is a centralized repository of structured, cleaned, and verified data that has been extracted, transformed, and loaded from various sources. These steps are commonly called ETL, which stands for Extract, Transform, Load. This data processing methodology involves extracting data from multiple sources, transforming it to meet business needs, and loading it into a destination for analysis and consultation." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"A lake based on the medallion architecture combines the best of lakes and data warehouses. By breaking down silos and eliminating data duplication, it becomes a standard for building data platform architecture." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"A lakehouse is a data storage space that hosts and manages all types of data in one place (structured, semi-struc-tured, and unstructured), allowing different tools to normalize and examine this data according to organizational requirements and/or individual choices. A lakehouse thus combines the best aspects of a data lake and a data warehouse by eliminating data duplication and friction related to ingestion, transformation, and sharing of data within the organization, all in the open format, Delta Lake." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Considered by many companies as the next generation of data architecture, the data mesh represents the natural evolution of traditional data lakes and data warehouses. While the latter are often limited by their centralized and monolithic structure, the data mesh aims to enable companies to deploy a more flexible, responsive, and massively scalable data strategy." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"[...] the data mesh architecture of Microsoft Fabric primarily supports the organization of data into domains and federated governance [...]  Hierarchizing data within OneLake by domain simplifies organizing data, allowing a data producer to easily identify where to deposit data or a data consumer to filter and discover content by functional domain. But it also enables the distribution of governance responsibilities by defining roles and responsibilities for teams in charge of specific domains."  (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Data transformation sits at the heart of every successful data platform, serving as the critical bridge between data ingestion and data consumption. While basic transformations might involve simple cleaning and formatting, advanced transformation techniques encompass complex operations such as data enrichment, sophisticated deduplication, machine learning-based predictions, and the creation of derived metrics that weren’t present in the original data sources. These processes are essential for organizations looking to extract maximum value from their data investments." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Data virtualization is a technique that allows users and applications to access and interact with data stored in multiple, physically separate locations as if it were all in one place. Instead of moving or duplicating data, virtualization creates a logical layer that connects to the original sources and presents them in a unified view. This means users can query, analyze, or combine data from different systems - cloud storage, databases, or other platforms - without needing to know where or how the data is stored." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Fabric integrates the various technologies needed for an end-to-end data project (namely, ingestion, preparation, storage, processing, enrichment, analysis, visualization, and data sharing) within a single platform accessible as Software as a Service (SaaS), meaning via a simple connection on a web browser. This reduces complexity, costs, and delays related to using multiple tools and technologies, and eliminates all the operational maintenance of infrastructure serving data analytics needs." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Fabric Pipelines provide reliable and efficient end-to-end orchestration of data flows, managing ingestion, transformation, and loading through a sequence of steps that can leverage various data processing engines. They allow centralizing and orchestrating data movements from various sources, thanks to advanced connectivity features, and with great scalability. Built-in monitoring tools enable real-time tracking of data flow status and quick detection of anomalies or errors." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Fabric relies on a lakehouse, a data storage model that combines the benefits of a data lake and a data warehouse. Within Fabric, the various data analytics and processing tools rely on a data lake that collects and stores data in its original format, whether structured, semi-structured, or unstructured, without the need to transform or normalize it beforehand. The lakehouse approach then enables converting these diverse data formats into a single format (i.e., compatible with all the data processing engines offered by Fabric) and in an open format, allowing other market vendors to interact with data in the Fabric lakehouse." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"In Fabric, a domain represents a way to logically group data corresponding to specific functional areas. Domains are frequently used to organize data by business sector in order to manage it according to each sector’s regulations, specifics, and requirements." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"It should be noted that, unlike Dataflow Gen2, in pipelines, it is not mandatory to enable staging to load data into a warehouse. Indeed, pipelines are designed for more general orchestration scenarios where you can combine various activities such as transformations, API calls, and so on to create complex workflows. They are not specifically focused on data preparation but rather on end-to-end process automation. Pipelines are more flexible and used for a variety of orchestration tasks, whereas Dataflow Gen2 is specifically designed for data preparation and transformation, hence the requirement for staging in that case." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"The hub and spoke, or 'star network', is a data architecture model that centralizes data from various sources into a single hub, such as a data warehouse or data lake. The hub serves as the source of truth for data and provides standardized schemas and formats. The spokes are the various applications or services that consume data from the hub for different purposes, such as analytics, reporting, or ma-chine learning. Spokes can also perform transformations or aggregations on data before presenting it to end users. The hub and spoke architecture aims to simplify data integration and management by reducing complexity and redundancy in data pipelines" (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"The problem with data lakes is that they have several drawbacks preventing them from being the perfect or ideal solution. The first drawback is an organizational problem: (•) How to organize data in the lake (•) How to classify, catalog, secure, document, and find it (•) How to avoid the lake turning into a swamp where data is mixed, duplicated, obsolete, or inaccessible (•) How to manage quality, governance, and traceability in the lake."(Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"The transformation phase represents the most resource-intensive stage of most data projects, often consuming 60-80% of total project time and effort. This significant investment stems from the inherent complexity of converting raw, inconsistent data into clean, structured, and enriched information ready for business use. Every data quality issue must be identified and resolved, every business rule must be correctly implemented, and every integration point must be properly validated. This meticulous work serves as the essential bridge between raw data ingestion and meaningful business insights." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"This transition to OneDrive highlights the importance of governance adapted to new methods of collaborative work and data sharing. The idea of OneLake is, therefore, based on this same concept: rather than subscribing to a data lake technology that must be maintained, why not simply subscribe to a storage service that offers a layer of abstraction over the complexities of these data storage infrastructures? As a result, the data lake becomes a controlled or governed environment, but still accessible to users who can view it as a simple and intuitive way to securely share data with their colleagues and IT teams."(Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"Traditionally, data engineers are responsible for the first steps of data transformation, commonly referred to as the transition from the 'bronze' stage to the 'silver' stage. This phase includes the normalization of raw data to clean and organize it into a structured and accessible format. Data Engineers ensure that data is properly ingested, stored, and prepared for subsequent steps. Their work focuses on building robust data pipelines and applying basic transformations that make the data usable. Next, responsibility may be handed over to an analytics engineer, who takes charge of the transition from the 'silver' stage to the 'gold' stage. This step involves more complex transformations aimed at refining, enriching, and modeling the data to meet specific analytical needs. The analytics engineer ensures that the data is ready to be used in reports, dashboards, and advanced analyses. The transition to the 'gold' stage means that the data is fully prepared for analytic use, providing strategic insights from consolidated data sources." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"While Fabric provides all the traditional tools that data specialists use daily to work on data integration and processing projects, it also offers new intuitive interfaces to enable business users, citizen analysts, or business analysts to interact with their data regardless of their skill level. The primary goal is to meet the needs and expectations of these users, who often do not benefit from data analytics and processing tools because they are too complex to use, even though they are themselves the main consumers and producers of data within organizations." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

"With Fabric, organizations can unlock the full potential of AI and machine learning in their data workflows. First, it provides users with all the tools necessary to create and deploy AI and machine learning models; users can use the frameworks and languages of their choice. Next, it enables these users to benefit from native integration of models that enrich the data present within Fabric with advanced cognitive analytics, such as vision and language, for example, and leverage the new capabilities of generative AI. Finally, it supports users at every stage of their data project with intelligent assistants that help create data integration flows, develop transformations or analyses, build data visualization reports, and even answer business questions by leveraging existing reports and semantic models to deliver contextual insights instantly." (Christopher Maneu et al, "The Definitive Guide to Microsoft Fabric From discovery to building a unified, secure, and scalable data platform", 2025)

📉Graphical Representation: Space (Just the Quotes)

"The zero of the scale should appear on every chart, and should shown by a heavy line carried across the sheet. If this is not done the reader may assume the bottom of the sheet to be zero and so be misled. The scale should be graduated from zero to a little over the maximum figure to be plotted on the charts, so that there will be a space between the highest peak on the curve and the top of the chart." (Allan C Haskell, "How to Make and Use Graphic Charts", 1919)

"A chart without a border line has several advantages. It is not limited to a designated area. The irregular white space surrounding it makes it more adaptable to any page size. It may be more readily placed either horizontally or vertically on the page, so long as the reduction in the size of the chart does not destroy legibility of lettering." (Mary E Spear, "Charting Statistics", 1952)

"Since the chief purpose of the nomogram is to make exact data available for operational use, its chief competitor is the table. Operational tables may break Ehrenberg's two-digit rule, since they are not used to detect general trends but to provide exact data for some operational purpose. The choice  between nomogram and table involves a complex tradeoff among cost, space, convenience, accuracy, and speed. These tradeoff situations provide one good reason why no one graphic format is suitable for all purposes. Of course, there can be good methods (sarisfying solutions) for particular cases." (Michael Macdonald-Ross, "Graphics in Texts", Review of Research in Education Vol. 5, 1977)

"An especially effective device for enhancing the explanatory power of time-series displays is to add spatial dimensions to the design of the graphic, so that the data are moving over space (in two or three dimensions) as well as over time. […] Occasionally graphics are belligerently multivariate, advertising the technique rather than the data." (Edward R Tufte, "The Visual Display of Quantitative Information", 1983)

"Graphical excellence is the well-designed presentation of interesting data - a matter of substance, of statistics, and of design. Graphical excellence consists of complex ideas communicated with clarity, precision, and efficiency. Graphical excellence is that which gives to the viewer the greatest number of ideas in the shortest time with the least ink in the smallest space. Graphical excellence is nearly always multivariate. And graphical excellence requires telling the truth about the data." (Edward R Tufte, "The Visual Display of Quantitative Information", 1983)

"A time series is a special case of the broader dependent-independent variable category. Time is the independent variable. One important property of most time series is that for each time point of the data there is only a single value of the dependent variable; there are no repeat measurements. Furthermore, most time series are measured at equally-spaced or nearly equally-spaced points in time." (William S Cleveland, "The Elements of Graphing Data", 1985)

"Binning has two basic limitations. First, binning sacrifices resolution. Sometimes plots of the raw data will reveal interesting fine structure that is hidden by binning. However, advantages from binning often outweigh the disadvantage from lost resolution. [...] Second, binning does not extend well to high dimensions. With reasonable univariate resolution, say 50 regions each covering 2% of the range of the variable, the number of cells for a mere 10 variables is exceedingly large. For uniformly distributed data, it would take a huge sample size to fill a respectable fraction of the cells. The message is not so much that binning is bad but that high dimensional space is big. The complement to the curse of dimensionality is the blessing of large samples. Even in two and three dimensions having lots of data can bc very helpful when the observations are noisy and the structure non-trivial." (Daniel B Carr, "Looking at Large Data Sets Using Binned Data Plots", [in "Computing and Graphics in Statistics"] 1991)

"Many of the applications of visualization in this book give the impression that data analysis consists of an orderly progression of exploratory graphs, fitting, and visualization of fits and residuals. Coherence of discussion and limited space necessitate a presentation that appears to imply this. Real life is usually quite different. There are blind alleys. There are mistaken actions. There are effects missed until the very end when some visualization saves the day. And worse, there is the possibility of the nearly unmentionable: missed effects." (William S Cleveland, "Visualizing Data", 1993)

"In preparing bar charts, make certain that the space separating the bars is smaller than the width of the bars. Use the most contrasting color or shading to emphasize the important item, thereby reinforcing the message title." (Gene Zelazny. "Say It with Charts: The executive’s guide to visual communication" 4th Ed., 2001)

"The suggestions for making the most of bar charts also apply to column charts: make the space between the columns smaller than the width of the columns; and use color or shading to emphasize one point in time more than others or to distinguish, say, historical from projected data." (Gene Zelazny. "Say It with Charts: The executive’s guide to visual communication" 4th Ed., 2001)

"Coordinates are sets that locate points in space. These sets are usually numbers grouped in tuples, one tuple for each point. Because spaces can be defined as sets of geometric objects plus axioms defining their behavior, coordinates can be thought of more generally as schemes for mapping elements of sets to geometric objects." (Leland Wilkinson, "The Grammar of Graphics" 2nd Ed., 2005)

"[...] the First Principle for the analysis and presentation data: 'Show comparisons, contrasts, differences'. The fundamental analytical act in statistical reasoning is to answer the question "Compared with what?". Whether we are evaluating changes over space or time, searching big data bases, adjusting and controlling for variables, designing experiments , specifying multiple regressions, or doing just about any kind of evidence-based reasoning, the essential point is to make intelligent and appropriate comparisons. Thus visual displays, if they are to assist thinking, should show comparisons." (Edward R Tufte, "Beautiful Evidence", 2006)

"Closely spaced lines produce moiré vibration, usually at its worst when data-lines (the figure) and spaces (the ground) between data-lines are approximately equal in size, and also when figure and ground contrast strongly in color value." (Edward R Tufte, "Beautiful Evidence", 2006)

"Most techniques for displaying evidence are inherently multimodal, bringing verbal, visual. and quantitative elements together. Statistical graphics and maps arc visual-numerical fields labeled with words and framed by numbers. Even an austere image may evoke other images, new or remembered narrative, and perhaps a sense of scale and quantity. Words can simultaneously convey semantic and visual content, as the nouns on a map both name places and locate them in the two - space of latitude and longitude." (Edward R Tufte, "Beautiful Evidence", 2006)

"The notion of outcomes covering a space is a very useful mental image, as it ties in strongly with the use of Venn diagrams and tables for clarifying the nature of possible events resulting from a trial. There are two important aspects to this. First, when enumerating the various outcomes that comprise an event, the number of (equally. likely) outcomes should correspond, visually, with the area of that part of the diagram represented by the event in question - the greater the probability, the larger the area. Secondly, where events overlap (for example, when rolling a die, consider the two events 'getting an even score' and 'getting a score greater than 2' ), the various regions in the Venn diagram help to clarify the various combinations of events that might occur." (Alan Graham, "Developing Thinking in Statistics", 2006)

"Radar charts are almost always the result either of space-saving attempts or of doubtful theories about the desirability of 'symmetrical' plots, in which scores on all dimensions are similar, so giving an approximation to a circle. Their scales offer unlimited scope for manipulation in achieving this lunatic ambition." (Nicholas Strange, "Smoke and Mirrors: How to bend facts and figures to your advantage", 2007)

"There are some chart types that occasionally appear in print but are so bad that they serve neither honesty nor deceit. Among these monuments to human ingenuity at the expense of common sense are the concentric donut and overlapping segments. The concentric donut is really just a bar or column chart bent back on itself to save space. However as anyone who has ever watched a two or four hundred metre race will know, to make sense of the order of arrival at the tape you have to stagger the start to take account of the bend in the track. Blithely ignoring this problem, the concentric donut uses to diminish the difference between the inner and the outer absolute values by anything up to 2.5 times." (Nicholas Strange, "Smoke and Mirrors: How to bend facts and figures to your advantage", 2007)

"Mosaic plots become more difficult to read for variables with more than two or three categories. One way out is to assign a constant space for all possible crossings of categories. This way, the data from the r×c table are plotted in a table-like layout. Whereas this regular layout makes it much easier to compare values across rows and columns, the plot space is used less efficiently than in a mosaic plot." (Martin Theus & Simon Urbanek, "Interactive Graphics for Data Analysis: Principles and Examples", 2009)

"One big advantage of parallel coordinate plots over scatterplot matrices. (i.e., the matrix of scatterplots of all variable pairs) is that parallel coordinate plots need less space to plot the same amount of data. On the other hand, parallel coordinate plots with p variables show only p − 1 adjacencies. However, adjacent variables reveal most of the information in a parallel coordinate plot. Reordering variables in a parallel coordinate plot is therefore essential." (Martin Theus & Simon Urbanek, "Interactive Graphics for Data Analysis: Principles and Examples", 2009) 

"Shingling is the process of dividing a continuous variable into - possibly overlapping - intervals in order to convert a continuous variable into a discrete variable. Shingling is quite different from conditioning on categorical variables. Overlapping shingles/intervals lead to multiple representation of data within a trellis display, which is not the case for categorical variables. Furthermore, it is challenging to judge which intervals/cases have been chosen to build a shingle. Trellis displays represent the shingle interval visually by an interval of the strip label. Although no plotting space is wasted, the information on the intervals is difficult to read from the strip label. Despite these drawbacks, there is a valid motivation for shingling […]." (Martin Theus & Simon Urbanek, "Interactive Graphics for Data Analysis: Principles and Examples", 2009) 

"The data [in tables] should not be so spaced out that it is difficult to follow or so cramped that it looks trapped. Keep columns close together; do not spread them out more than is necessary. If the columns must be spread out to fit a particular area, such as the width of a page, use a graphic device such as a line or screen to guide the reader’s eye across the row." (Dennis K Lieu & Sheryl Sorby, "Visualization, Modeling, and Graphics for Engineering Design", 2009)

"Trellis displays introduce the concept of shingling. Shingling is the process of dividing a continuous variable into - possibly overlapping - intervals in order to convert a continuous variable into a discrete variable. Shingling is quite different from conditioning on categorical variables. Overlapping shingles/intervals lead to multiple representation of data within a trellis display, which is not the case for categorical variables. Furthermore, it is challenging to judge which intervals/cases have been chosen to build a shingle. Trellis displays represent the shingle interval visually by an interval of the strip label. Although no plotting space is wasted, the information on the intervals is difficult to read from the strip label. Despite these drawbacks, there is a valid motivation for shingling," (Martin Theus & Simon Urbanek, "Interactive Graphics for Data Analysis: Principles and Examples", 2009)

"Be aware that bar charts provide ample opportunities for chart junk. The space within the bars is enticingly empty and it is tempting to put images or textures in the background. Some designers even swap out the standard bars for graphics." (Brian Suda, "A Practical Guide to Designing with Data", 2010)

"The amount of information rendered in a single financial graph is easily equivalent to thousands of words of text or a page-sized table of raw values. A graph illustrates so many characteristics of data in a much smaller space than any other means. Charts also allow us to tell a story in a quick and easy way that words cannot." (Brian Suda, "A Practical Guide to Designing with Data", 2010)

"Sparklines aren't necessarily a variation on the line chart, rather, a clever use of them. [...] They take advantage of our visual perception capabilities to discriminate changes even at such a low resolution in terms of size. They facilitate opportunities to construct particularly dense visual displays of data in small space and so are particularly applicable for use on dashboards." (Andy Kirk, "Data Visualization: A successful design process", 2012)

"Area can also make data seem more tangible or relatable, because physical objects take up space. A circle or a square uses more space than a dot on a screen or paper. There’s less abstraction between visual cue and real world." (Nathan Yau, "Data Points: Visualization That Means Something", 2013)

"A space-filling layout has the property that it fills all available space in the view, as the name implies. [...] ne advantage of space-filling approaches is that they maximize the amount of room available for color coding, increasing the chance that the colored region will be large enough to be perceptually salient to the viewer. A related advantage is that the available space representing an item is often large enough to show a label embedded within it, rather than needing more room off to the side. In contrast, one disadvantage of space-filling views is that the designer cannot make use of white space in the layout; that is, empty space where there are no explicit visual elements. Many graphic design guidelines pertain to the careful use of white space for many reasons, including readability, emphasis, relative importance, and visual balance." (Tamara Munzner, "Visualization Analysis and Design", 2014)

"As with all design problems, vis design cannot be easily handled as a simple process of optimization because trade-offs abound. A design that does well by one measure will rate poorly on another. The characterization of trade-offs in the vis design space is a very open problem at the frontier of vis research." (Tamara Munzner, "Visualization Analysis and Design", 2014)

"Parallel coordinates visually encode data using two dimensions of spatial position. Of course, any individual axis requires only one spatial dimension, but the second dimension is used to lay out multiple axes. The scalability is high in terms of the number of quantitative attribute values that can be discriminated, since the high precisionchannel of planar spatial position is used. The exact number is roughly proportional to the screen space extent of the axes, in pixels. The scalability is moderate in terms of number of attributes that can be displayed: dozens is common. As the number of attributes shown increases, so does the width required to display them, so a parallel coordinates display showing many attributes is typically a wide and flat rectangle. Assuming that the axes are vertical, then the amount of vertical screen space required to distinguish position along them does not change, but the amount of horizontal screen space increases as more axes are added. One limit is that there must be enough room between the axes to discern the patterns of intersection or parallelism of the line  segments that pass between them." (Tamara Munzner, "Visualization Analysis and Design", 2014)

"Decision trees are also discriminative models. Decision trees are induced by recursively partitioning the feature space into regions belonging to the different classes, and consequently they define a decision boundary by aggregating the neighboring regions belonging to the same class. Decision tree model ensembles based on bagging and boosting are also discriminative models." (John D Kelleher et al, "Fundamentals of Machine Learning for Predictive Data Analytics: Algorithms, Worked Examples, and Case Studies", 2015)

"One thing to keep in mind with a table is that you want the design to fade into the background, letting the data take center stage. Don’t let heavy borders or shading compete for attention. Instead, think of using light borders or simply white space to set apart elements of the table." (Cole N Knaflic, "Storytelling with Data: A Data Visualization Guide for Business Professionals", 2015)

"When we’re at the point of communicating our analysis to our audience, we really want to be in the explanatory space, meaning you have a specific thing you want to explain, a specific story you want to tell - probably about those two pearls." (Cole N Knaflic, "Storytelling with Data: A Data Visualization Guide for Business Professionals", 2015)

"Linking is a powerful dynamic interactive graphics technique that can help us better understand high-dimensional data. This technique works in the following way: When several plots are linked, selecting an observation's point in a plot will do more than highlight the observation in the plot we are interacting with - it will also highlight points in other plots with which it is linked, giving us a more complete idea of its value across all the variables. Selecting is done interactively with a pointing device. The point selected, and corresponding points in the other linked plots, are highlighted simultaneously. Thus, we can select a cluster of points in one plot and see if it corresponds to a cluster in any other plot, enabling us to investigate the high-dimensional shape and density of the cluster of points, and permitting us to investigate the structure of the disease space." (Forrest W Young et al, "Visual Statistics: Seeing data with dynamic interactive graphics", 2016)

"A time series is a sequence of values, usually taken in equally spaced intervals. […] Essentially, anything with a time dimension, measured in regular intervals, can be used for time series analysis." (Andy Kriebel & Eva Murray, "#MakeoverMonday: Improving How We Visualize and Analyze Data, One Chart at a Time", 2018)

"Ideally, the charts are designed in a way that gives your audience clarity and lets them understand the key insights very quickly. Color choices, highlighting, annotations, and other ways of drawing attention to your findings help in the process. By leaving white or blank space around your charts, you are able to keep the focus of your audience on the key message rather than distracting or confusing them." (Andy Kriebel & Eva Murray, "#MakeoverMonday: Improving How We Visualize and Analyze Data, One Chart at a Time", 2018)

"Simplicity in design can be recognized in visualizations that are clear, easy to understand, uncluttered, and impactful. Nonessential items are removed from these visualizations so that the data stands out, giving it space and removing distractions. Simplicity in design pays careful attention to the overall layout and positioning of individual components, the balance of charts and text elements, and the choice of colors, fonts, and icons, as well as the clarity with which all of these elements communicate to the audience." (Andy Kriebel & Eva Murray, "#MakeoverMonday: Improving How We Visualize and Analyze Data, One Chart at a Time", 2018)

"The radial bar chart, also called the polar bar chart, arranges the bars to radiate outward from the center of a circle. This graph lies lowers on the perceptual ranking list because it is harder to compare the heights of the bars arranged around a circle than when they are arranged along a single flat axis. But this layout does allow you to fit more values in a compact space, and makes the radial bar chart well-suited for showing more data, frequent changes (such as monthly or daily), or changes over a long period of time." (Jonathan Schwabish, "Better Data Visualizations: A guide for scholars, researchers, and wonks", 2021)

"A semantic approach to visualization focuses on the interplay between charts, not just the selection of charts themselves. The approach unites the structural content of charts with the context and knowledge of those interacting with the composition. It avoids undue and excessive repetition by instead using referential devices, such as filtering or providing detail-on-demand. A cohesive analytical conversation also builds guardrails to keep users from derailing from the conversation or finding themselves lost without context. Functional aesthetics around color, sequence, style, use of space, alignment, framing, and other visual encodings can affect how users follow the script." (Vidya Setlur & Bridget Cogley, "Functional Aesthetics for data visualization", 2022)

"Like multimodal reading, data literacy relies on both primary literacy skills and numeracy skills to truly make sense of the third layer: reading and understanding graphs. Charts codify numbers visually into parameters, using stylized marks to embed additional layers of meaning and space to provide quantitative relationships. Beyond the individual chart, data visualizations create ensembles of charts." (Vidya Setlur & Bridget Cogley, "Functional Aesthetics for data visualization", 2022)

"Maps are a type of chart that can convey relationships about space and relationships between objects that we relate to in the real world. Their effectiveness as a communication medium is strongly influenced by a host of factors: the nature of spatial data, the form and structure of representation, their intended purpose, the experience of the audience, and the context in the time and space in which the map is viewed. In other words, maps are a ubiquitous representation of spatial information that we can understand and relate to." (Vidya Setlur & Bridget Cogley, "Functional Aesthetics for data visualization", 2022)

"Positive and negative space help create balance, but they also draw interest." (Vidya Setlur & Bridget Cogley, "Functional Aesthetics for data visualization", 2022)

"The sizes of charts in space reflect how we convey information to a reader. In a dashboard context, the content, size, and space that the various charts occupy should reflect the form and function of the main message. As you saw with the bento box metaphor from the introduction, there needs to be deliberate thought put into the placement and size of each individual chart so that they all work together in harmony." (Vidya Setlur & Bridget Cogley, "Functional Aesthetics for data visualization", 2022)

⚡️Jeroen ter Heerdt - Collected Quotes

"After the table is loaded or refreshed, the results for calculated tables and calculated columns are locked in and cannot be changed until the table is refreshed. The results are precomputed and aren’t dynamically determined. Most often, calculated tables are relatively easy to understand, precisely because you can inspect the DAX statement and predict the results. The same statement always returns the same result for the same parameters until the table is refreshed." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Another issue is that it’s extremely difficult in DAX to reliably and definitively refer to a value from an earlier (or later) row. These relative or absolute shifts from the current evaluation position are possible but surprisingly hard to do. After all, you’re looking at a visual on your screen that shows data in a certain order, so it makes sense that you think that it should be easy to refer to an earlier (or later) row. However, if you try to do so, you’ll soon discover DAX doesn’t work that way. This is because DAX statements are evaluated in the model, which does not sort the data in the same way as the data is sorted in your visual. For all you know, that row that was at the top of your visual, is somewhere in the middle of the data when the DAX is evaluated, so the whole idea of referring to an earlier or later row is meaningless." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Calculated columns are most often used to perform row-by-row calculations within a table - for example, to obtain the difference between two columns for each row. Calculated columns are static, meaning they’re calculated when the table is first loaded or refreshed, and their results cannot be changed until the table is refreshed again." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Calculation groups can help reduce the number of redundant measures using the same filter expression. Calculation groups provide a way to change the type of calculation without adding another measure to the model. In this way, you can avoid adding more measures and duplicating logic in multiple measures."  (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"[....] context transition happens in calculated columns, where a row context is present, and whenever you’re using a function that iterates over multiple values, such as SUMX. This last group of functions are conveniently called iterators." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Data may indeed be the new oil. But just like crude oil, data needs refining. It must be transformed into information. This is why we clean, combine, model, and visualize data. The output of all this work - whether you do it on your own, get some help, or use a (semi-)automatic process - includes reports and dashboards that provide insights into various aspects of the organization’s dealings, which decision-makers can then consume to make critical business decisions." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"DAX does not have any data connectors or ways to reach out to anything outside of Power BI to collect data. Therefore, all data must be connected to the semantic model first. After this has been done, you can use calculated tables to enrich your semantic model and apply calculations. Calculated tables let you add new tables based on data you loaded into the model. Instead of querying and loading values into your new table’s columns from a data source, you create a DAX formula to define the table’s values." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Measures Unlike calculated columns and calculated tables, measures aren’t precalculated or static. Their output is dynamically calculated as needed and is determined not only by their definition but also by the filter context in which they’re executed. The same definition can have a different meaning based on the filter context. Measures are evaluated within that filter context and often summarize multiple rows."(Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Power BI provides audit logs that contain information about all actions performed by users in the Power BI Service (cloud). Because this is limited to the web environment, nothing that occurs in Power BI Desktop is traced. The creation of visual calculations is also not traced as activity in audit logs but is covered in a generic activity named Update Report Content." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Roche's Maxim of Data Transformation, expressed by Matthew Roche of Microsoft, states that 'Data should be transformed as far upstream as possible, and as far downstream as necessary'. Upstream data is source data (for example, data in a database), whereas downstream data is data that has been transformed in some way (for example, data in a report). We mention this maxim because you can apply calculations to data that is upstream, downstream, or anywhere in between. [...] The further upstream you go, the closer to the origin of the data you are. The further downstream you go, the closer to the visualization on the report you are, like the lake at the bottom of the waterfall." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Row context can transform into filter context through a mechanism called context transition. Context transition takes any active row context and transforms it into a filter in the filter context. Multiple functions do this automatically." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Using CALCULATE can feel like riding a wild bull. You ride it, but you never feel fully in control." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Visual calculations are calculated in the context of the visual matrix. All model objects that are in the visual matrix can be used in a visual calculation. These can consist of columns from various tables, but also explicit measures saved in the model or implicit measures that are part of the visual." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Visual calculations are DAX calculations executed in the scope of a visual. They are by default executed on a row-by-row basis, much like a calculated column, but are calculated on the fly, like a measure. In contrast to both calculated columns and measures, visual calculations aren’t part of the semantic model in Power BI but instead are part of a visual, such as a chart. This means visual calculations don’t have to worry about filter context as much as measures need to do. In fact, the filter context is seen as external to the visual calculation on a visual. This doesn’t mean the visual calculation isn’t affected by or would ignore the filter context but rather that it’s applied on a different level. The filter context dictates what the measures and fields on the visual return, and the visual calculation takes those values as input for its evaluation. In other words, a visual calculation is only indirectly affected by filter context, not directly, the way a measure or field reference is." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"Visual calculations share behaviors with calculated columns and measures but also have important differences, particularly in how they can be used, where they are stored, and when they are computed. " (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"What makes DAX hard has little to do with the functions themselves. The problem is also not its syntax - although DAX is a functional language, which means it uses an “inside-out” syntax instead of the more commonly used “top-to-bottom” syntax that is most used in programming. This requires some rethinking, particularly if you are coming from a procedural programming background or if, for example, you have written macros in Excel. To read and understand a DAX statement, you must find the innermost piece, parse it, then go to the next layer, which takes the innermost piece as a parameter, and work your way outward [...]" (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)

"While it might be tempting to think about row context as a special filter on your table, we recommend not doing that. The row context is not a type of filter; it simply indicates to DAX which row is currently responsible for providing the values to perform the calculation and where the result of the calculation should go. Whether a column in the table is used in a particular calculation is irrelevant; all columns of the table are part of the row context when a calculation is performed." (Jeroen ter Heerdt et al, "Microsoft Power BI Visual Calculations: Simplifying DAX", 2026)