"(1) The degree to which a product, process, or project possesses some attribute of interest. (2) A measured quantity (such as size, effort, duration, or quality). (3) The distance between two points in a vector space." (Richard D Stutzke, "Estimating Software-Intensive Systems: Projects, Products, and Processes", 2005)
"A summarizable numerical value used to monitor business activity; it is also known as a fact." (Reed Jacobsen & Stacia Misner, "Microsoft SQL Server 2005 Analysis Services Step by Step", 2006)
"A metric is a measurement. When a plan is put into place, a way to measure the outcome is needed. When a market share forecast is created and the outcomes are measured at a future date, the planned metric is compared with the actual metric to determine the degree to which the metric was met. From this data, strategies can be revised and tactical options can be reconsidered." (Steven Haines, "The Product Manager's Desk Reference", 2008)
"A numerical value describing a procedure, process, product attribute, or goal. A distinction is made between basic metrics (that can be measured directly) and derived metrics which result from mathematical operations using basic metrics." (Lars Dittmann et al, "Automotive SPICE in Practice", 2008)
"a measurement of some parameter, usually used in the assessment of a technology, approach, or design." (Bruce P Douglass, "Real-Time Agility: The Harmony/ESW Method for Real-Time and Embedded Systems Development", 2009)
"A metric is a standard unit of measure, such as meter or mile for length, or gram or ton for weight, or, more generally, part of a system of parameters, or systems of measurement, or a set of ways of quantitatively and periodically measuring, assessing, controlling, or selecting a person, process, event, or institution, along with the procedures to carry out measurements and the procedures for the interpretation of the assessment in the light of previous or comparable assessments." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)
"Groupings of data, or numbers, that reflect specific measures or subjects." (Annetta Cortez & Bob Yehling, "The Complete Idiot's Guide To Risk Management", 2010)
"a calculated value based on measurements used to monitor and control a process or business activity. Most metrics are ratios comparing one measurement to another." (DAMA International, "The DAMA Dictionary of Data Management", 2011)
"A specific, measurable standard against which actual performance is compared." (Linda Volonino & Efraim Turban, "Information Technology for Management" 8th Ed., 2011)
"Generally, a unit of measure selected used to monitor and control a process." (DAMA International, "The DAMA Dictionary of Data Management", 2011)
"In a data warehouse, numeric facts that measure a business characteristic of interest to the end user." (Carlos Coronel et al, "Database Systems: Design, Implementation, and Management" 9th Ed., 2011)
"Measurement of a particular characteristic of a task (for example, duration, effort, quality, cost, value delivered, or customer satisfaction)." (Charles Cooper & Ann Rockley, "Managing Enterprise Content: A Unified Content Strategy" 2nd Ed., 2012)
"1. A value from measuring a certain program or component attribute. Finding metrics is a task for static analysis. 2. A measurement scale and the method used for measurement." (Tilo Linz et al, "Software Testing Foundations" 4th Ed., 2014)
"A method of measuring something. It provides quantifiable data used to gauge the effectiveness of a process; metrics are commonly used to measure the effectiveness of a help desk." (Darril Gibson, "Effective Help Desk Specialist Skills", 2014)
"A value that you use to study some aspect of a project. A metric can be an attribute (such as the number of bugs) or a calculated value (such as the number of bugs per line of code)." (Rod Stephens, "Beginning Software Engineering", 2015)
"A measurement used to support the monitoring of a key performance indicator (KPI). A metric can have targets and can be used as a service level." (by Brian Johnson & Leon-Paul de Rouw, "Collaborative Business Design", 2017)
"Facts and figures representing the effectiveness of business processes that organizations track and monitor to assess the state of the company." (Jonathan Ferrar et al, "The Power of People: Learn How Successful Organizations Use Workforce Analytics To Improve Business Performance", 2017)
"A metric is the measurement of a particular characteristic of a company’s performance or efficiency. Metrics are the variables whose measured values are tied to the performance of the organization. They are also known as the performance metrics because they are performance indicators." (Amar Sahay, "Business Analytics" Vol. I, 2018)
"A measurable quantity that indicates progress toward some goal." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)
"Any number (often one calculated using two or more input numbers) used to evaluate some part of an organization's performance." (Marci S. Thomas & Kim Strom-Gottfried, "Best of Boards" 2nd Ed., 2018)
"Metrics are agreed-upon measures used to evaluate how well the organization is progressing toward the Portfolio, Large Solution, Program, and Team’s business and technical objectives." (Dean Leffingwell, "SAFe 4.5 Reference Guide: Scaled Agile Framework for Lean Enterprises" 2nd Ed., 2018)
"In a machine learning context, a metric is a measure of how good or bad a particular model is at its task. In a software context, a metric is a measure defined for an application, program, or function." (Alex Thomas, "Natural Language Processing with Spark NLP", 2020)
"A
business calculation defined by an expression built with functions, facts,
attributes, or other metrics." (Microstrategy)
"A measurement scale and the method used for measurement" (ISO 14598)
"Quantifiable measures used to track, monitor, and gauge the results and success of various business processes. Metrics are meant to communicate a company’s progression toward certain long and short term objectives. This often requires the input of key stakeholders in the business as to which metrics matter to them." (Insight Software)
"Tools designed to facilitate decision making and improve performance and accountability through collection, analysis, and reporting of relevant performance-related data." (NIST SP 800-55)