Why Turnover Are a Big Deal (In Basketball)

I was talking with someone about SC's turnover woes, and he just couldn't see why it was such a big deal. By his basic analysis, most teams make about 45% of their two point attempts and about 33% of their three point attempts. He also guessed that teams probably take about twice as many two point field goal attempts compared to threes, and performed the basic math using a handheld calculator*. By this method he got that on average a team would score about 0.93 points, on average, off of a turnover.

This is actually a pretty good guess. The only possiblilities that he did not take into account were the chance of going to the free throw line, because of a foul either before or suring a shot, which would increase the aforementioned score off of a turnover. Even, scoring only a little over one point per turnover should not be much to get worked up over considering that we're more concerned about the difference between the competing teams turnovers. However, the analysis is missing one crucial point: the fact that turnovers count just as much as a lost possesion for the team that turns the ball over.

So using a more in depth analysis, and some stats from si.cnn.com and kenpom.com, we can look at the real impact of turnovers using USC and ucla as an example. USC turns the ball over on average 16.9 times per game and scores about 1.06 points per possession (PPP). ucla on the other hand averages 14.2 TOs per game and scores 1.16 PPP. This means that right now, if USC and ucla were to play a statistically "average" game against eachother, SC would score 15.1 points off of ucla turnovers, while the bruins would score 19.6 off of Trojan turnovers for a difference of 4.5 points in favor of our rivals.

4.5 points may not seem like a big deal, but considering that a team would need two possesions of scoring and holding the opponent scoreless to close this gap makes it seem more significant. More importantly though, the average margin of victory between USC and ucla in their last five basketball games is 5.6 points, so turnovers really start to become a big deal. 

* If a team takes twice as many two as threes, that means that 33% of the time they shoot from beyond the arc. Here is what my friend entered into his calculator:         [(.667)*(.45)*2] + [(.333)*(.33)*3] = .93