Does Spreading the Ball Around Make a Passing Attack More Efficient?

Part of analyzing an NFL team’s passing game is measuring the distribution of passing stats among its receivers: targets, yards, touchdowns, etc. A good way to do this is looking at the percentage distribution to different receivers, i.e. the WR1 received 25 percent of receiving yards, the WR2 got 15 percent, and so on. This is useful when projecting stat lines for receivers, but doesn’t give us an easy way of comparing generally how concentrated one passing game is versus another.

A commenter at Chase Stuart’s Football Perspective gave him an idea from the finance world for calculating portfolio concentration, which Stuart used to conclude that teams are spreading it around more these days. The formula sums the squared passing yard ratios for each receiver to form a single number, or what Stuart calls the concentration index. The more spread out a passing game, the lower the concentration index, and vice versa.

I decided to dig into concentration index a bit more to see if we can learn anything about the benefits or costs of have a diversified passing game. (more…)

Deshaun Watson, Mitchell Trubisky and the Importance of Sample Size

I tend to ignore the specifics of most NFL mock drafts, but I was happy to see Rotoworld’s Josh Norris recognize the importance of sample size while recently predicting that the analytical wizards with the Cleveland Browns will prefer Deshaun Watson to Mitchell Trubisky come draft day.

(We should mention that everything written below regarding Watson’s larger sample also applies to Patrick Mahomes, who had more pass attempts than Watson at a similar yards per attempt.)

To those who are familiar with statistics generally, the concept that the Browns would want a larger sample for their potential franchise quarterback isn’t tremendously difficult to grasp. But it was still a pleasant surprise to see someone in the larger draft community weave this thinking into his analysis, especially when some mock drafts still forecast the Browns to make terrible strategic decisions from an analytical perspective, including taking a running back in the middle of the first round.

We know that bigger is better when it comes to sample size, and various models, including Football Outsiders’ QBASE – developed by now Browns’ senior strategist for player personnel Andrew Healy –  have shown that quarterbacks with longer college careers are more likely to be successful in the NFL. But is there a way we can truly peel apart the analysis and see the nuts and bolts of why this is so? (more…)