clock menu more-arrow no yes mobile

Filed under:

Can The Jayhawks Have an Elite Defense Without Turnovers?

John Rieger-USA TODAY Sports

Kansas finished 31st in adjusted defensive efficiency in the Pomeroy Ratings last year, and are currently 18th. While neither number is terrible, it's also a far cry from 5th and 3rd, where they were the two years previous.

I also noticed that Kansas finished 292nd in turnover percentage last season, and they rank 292nd this year as well. They have never been particularly great under Bill Self, but the percentage has gotten even worse lately.

Coming into writing this post, I didn't think turnovers had much to do with PPP allowed. At best, it meant that there would be more opportunities for opposing offenses to go on spurts where hey shot a high percentage, but it probably wouldn't have an impact either way.

First, a game by game look at this year. Note: I used points allowed per 10 possessions rather than PPP to make the graph look nicer:

The correlation here is .37. For more on correlations you can read here, but the long and short of it the closer you get to 1 or negative 1, the more closely related the terms are. So in the chart above, the general relationship is that the more turnovers Kansas forces, the fewer points it allows. On first glance, it might not be a strong relationship, but according to Dean Oliver's four factors, turnover rate accounts for about 25% of a team's defensive efficiency. So could turnovers be more important to Kansas's defensive success than we think?

But that's just one season. Let's look at Bill Self's entire tenure.

The correlation here is .61, and we are starting to get even higher.

Lastly, I noticed the last three years seem to be even more of an outlier: Kansas's PPP allowed has gone up every year, and its turnover rate has fallen every year. The correlation between TOs forced and PPP allowed? .91.

It seems fairly obvious that Kansas needs to force more turnovers in order to truly be an elite defense based on just these numbers, though it is worth noting that some teams, like Virginia this year and Arizona last year, have been elite defensive teams without the ability to force turnovers. However, those teams also had elite rim protection and the ability to keep teams away from the rim, two things Kansas doesn't have right now. The Jayhawks are currently 87th at opponents shots near the rim and 82nd in opponents' field goal percentage at the rim (hoop-math).

Turnovers being important to the KU defense seems fairly obvious in retrospect, but it caused me to have another thought. Often times KU's offense goes on big spurts and those spurts are created by turnovers, so I took a look at PPP scored compared to steal rate (steal rate because live ball turnovers often lead to to fast break opportunities and those turnovers are more influenced by the defense rather than relying on an offense's mistakes).

Here the correlation is just .206, so there hasn't been much of a relationship between steal rate and PPP (which surprised me a bit).

Again, small sample size so let's look at Bill Self's tenure:

Here the correlation is just .01 so there is absolutely no relationship between the number of live ball turnovers and the points it scores. I honestly did not expect that, but sometimes there is just as much value in being wrong as there is in being right.

So what can we conclude here? Honestly I am not sure. Without an elite rim protector, unless Hunter Mickelson gets a lot more playing time, it is nearly impossible to play high pressure defense in the half court without giving up a ton of layups, as we saw against Florida. And as we all know Bill Self doesn't like pressing full court.

The one major takeaway for me is that a good rim protector is even more important than I already thought. Not only does he affect scoring at the rim and how often teams shoot at the rim, it seems a good rim protector can also have an impact on turnover rates, and forcing turnovers is likely more important to good defense than I had thought. So, play Hunter Mickelson more, hope that Cliff Alexander stays out of foul trouble, and play pressure defense up top. Or, continue to play underneath guys and turn games into jump shot competitions. We're bound to get lucky sometime.