15 Ways to Check Data

My suggestions for how to deal with data proof are in the main column. I asked readers for their suggestions, and you guys came up with several great additions to the process of checking data:

1. To prove causality, you need three things: co-variation (aka, correlation), time order (to cause B, A has to happen first) and non-spuriousness.

2. Look at the depth of correlation (not just the direction but the amount of movement). What happens when "X" changes 5% -- does it correlate with a 15% change in Y? Do other changes in "X" change with Y? Is there a it tapering off of the effect? Does it invert? Are the increases linearly or non-linearly?

3. Always beware of "ceteris paribus." Translation: "all other things being equal." For the most part, all other things are very rarely equal. ...