Cost model
Measure the whole reporting loop, not only the final build time.
A report can take thirty minutes to assemble after five hours of preparation. If you only measure the last step, the business case for fixing it looks weaker than it really is.
Collect
Time spent exporting, requesting, chasing, and gathering data from different places.
Clean
Time spent deduplicating, renaming fields, filling gaps, and correcting obvious errors.
Explain
Time spent defending numbers, answering source-of-truth questions, and clarifying what changed.
