18 January 2010

Levels of Accuracy in Reporting

    Correlated with the level of detail, another aspect that needs to be considered in reports is results’ levels of accuracy – how much the data reflect the reality at each level of detail. Because the integration between modules of the same or different systems brought some of the attributes from one module into the other (e.g. Document Numbers, UIDs, Dates), the reports can consider the respective attributes in queries without involving the modules they come from. Thus for example in order to create an AP (Account Payables) Invoices report, could be sufficient to use the GL (General Ledger) Date stored in AP without using the GL data directly; on the other side, a more accurate report is obtain when using the AP and GL data, such a report could include also the manual postings made in GL and not available in AP. Typically the data from one module that are stored in another modules, should be in synch, though there could be exceptions and exceptions. In the end it is developer’s task to understand the level of accuracy/detail the users need; in general it doesn’t always make sense to provide the highest level of accuracy/detail when the user needs only some rough number, as higher level of accuracy/details equate with more effort and more tables added to a report.

    When considering the different levels of accuracy/detail within reports, given two modules/entities A and B, we might end up created a set of reports with:
a.  all records from A
b.  all records from B;
c.  all records from A and matching records from B, and vice-versa;
d.  all records from A and aggregated data from B when the level of detail is changed.
e.  aggregated data from A vs. aggregated data from B in case of many-to-many cardinality, the aggregation being made at a level of detail in which the amounts are not duplicated.
f.  mismatches between A and B for the same scope (it can be shown at different levels of details).

    These scenarios would allow Users to choose the report with the needed level of detail/accuracy, though covering all existing scenarios could be quite expensive, not to neglect the fact that there are reports spanning more than 2 modules. On the other side, two reports for A and B would be sufficient as long as the reference attributes between modules are provided, falling in Users’ task to match and aggregate the data, though also this alternative could prove to be problematic because of the volume of data, synchronization issues between data sets or lack of adequate skill set, and all related issues. The first solution is the ideal, the second is workable, though in the end it depends what makes the users happy….

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