BACKGROUNDWhy a dashboard can look correct and still be wrong
A chart can be neat, colourful and completely wrong if a duplicate row, missing period, invalid date or broken join entered the model. In reporting work, the question is not only “Can I calculate the KPI?” but “Can I prove the number is safe to publish?”
PROBLEMThe problem I wanted to solve
I wanted a repeatable UAT layer that checks the analytical models before their numbers are shown publicly, and that keeps warnings visible instead of hiding them.
TASKWhat I built
I created a catalogue of 22 validation tests covering completeness, uniqueness, allowed values, date logic, keys, ranges and source coverage. Each test has an expected result, actual result, severity and PASS/WARN/FAIL outcome.
TOOLS I USED
What each tool was doing
SQL / Python checksRun repeatable tests against the analytical datasets.
Data dictionaryDefine what fields and valid values should look like.
UAT rulesSeparate blocking failures from explainable warnings.
Publication gateStop a failed analytical run from silently replacing trusted numbers.
NOW THE ANALYSIS STARTSWith the problem and data purpose clear, the next section shows the result first. The detailed steps below then show exactly how I got there.