“Don’t Panic!” – The Hitchhikers Guide to the Galaxy
I often find that when business users are faced with large, even colossal, discrepancies in data sets, their first response is sheer panic. For me, the larger the discrepancy the calmer I am about it. Why? Because discovering source problems in data sets is almost always much easier the larger they are. The truly bedevilling problems are the inconsistent, small, and seemingly random discrepancies that occur.
What do I find the number one cause of numbers being 5, 10 or even hundreds of times greater than they should be? A time series snapshot that is summing all time periods. This is remarkably easy to fix, and can happen easily in a data cube without proper current time period settings. It is a common mistake for junior report developers, especially when they are expecting to see current period only.
Other common and simple problems include rounding errors or inconsistencies, improper unit of measure calculations, unexpected null values nixing a summarization total, or cube update failures. Always check for obvious and easy solutions first, and work your way down to more complicated resolutions as necessary. Note when a problem started and attempt to isolate what has changed since then. Be methodical and don’t panic!