It simply measures a teams' inconsistency in scoring throughout their schedule. However, if a team plays a BAD team, they should expect to do very well, and vice versa. In order to account for this, the better measure is the standard deviation in Actual-Expected efficiencies. And using only conference play is stupid--it gives us a sample size that is very small.
There are actually two more factors we must consider to get an accurate number of a teams' consistency, and only one that I can factor in (at the moment). The first is that offense and defense BY THEMSELVES are relatively unimportant. Examples being: Wright State has the 10th best adjusted Defense, but is 83rd overall in kenpom.....also: Notre Dame has the 6th best adjusted Offense and is 36th overall in kenpom. As we all know, it is the COMBINATION of these two that makes a team good. (You can have a 'bad' defensive day and win by 30). So instead of using offensive and defensive efficiencies, we should just use Efficiency Margins. (That is, one team's points per possession minus their opponents').
The second is this: if one team has a high standard deviation, but plays teams with high standard deviation, then their actual consisency is better than the numbers suggest. Unfortunately at this time I don't have the time to calculate this adjustment.
So let's look at consistency:
I call it the Rice-Factor. Tyrese Rice (and Boston College) is the reason for some of the most inconsistent team play in recent college basketball history (Beating Duke and Carolina, losing to St. Louis and Harvard).
Rice Factor: Standard Deviation of Actual Minus Expected Offense or Defense
Here's a random list of teams I think are inconsistent, and ones that John Gasaway calculated to be inconsistent.
Georgetown: .203 PPP
West Virginia: .201 PPP
Notre Dame: .174 PPP
Kentucky: .171 PPP*
Boston College: .171 PPP
Duke: .167 PPP
Tennessee: .140 PPP*
Arizona: .127 PPP*
Arizona is inSANELY consistent. John Gasaway getting mad at their offensive consistency is silly.
And poor Georgetown.