Verification.
THE DATA
Where did it come from? What period does it cover? Does the total match the source system? How many records, and is that what you expected? What is missing?
THE PREPARATION
What was excluded, and why? What was cleaned or corrected? Were duplicates checked? Are categories consistent?
THE METHOD
What exactly was calculated? Does every formula cover the full range? Were periods compared like with like? Is the sample large enough to conclude anything?
THE CONCLUSION
Is there a comparison? Could something else explain this? What would disprove it, and was that checked? Does the conclusion exceed what the data supports?
THE PRESENTATION
Are the underlying numbers given alongside percentages? Do the charts start where they should? Is uncertainty stated?
IF ANY ANSWER IS UNKNOWN
Find out before acting on it.
