## Friday, January 25, 2013

### Is NU recruiting on solid ground?

Brandon Vogel at Hail Varsity has a good article about the history of NU recruiting rankings over the last 25 years.

He maintains that NU is in a good position with our current recruiting.

I think that he's being a bit optimistic.

Using the recruiting ranks he posted and the W/L% for each year, I built a chart to determine the best correlation between recruiting rankings and W/L%. I used the current year ranking (what Brandon posted) and 2,3,4,5, and 6 year moving averages.

What I found was that best correlation between ranking and a year's W/L% is a 6-year moving average.

Current Year6 year average5 year average4 year average3 year average2 year average
Season W/L%-0.390-0.579-0.513-0.500-0.514-0.483

Using current year recruiting averages had the worst correlation, which is not surprising...what is surprising is that recruiting classes from 5 and 6 years prior to the current year could still have an effect on the season outcomes. Whether this is 'culture of winning' or something else merits further examination I think.

Now, knowing that a 6-year moving average is the strongest correlation to season W/L%, I can compute a regression equation based on the 6-year moving averages between 1992 and 2012 and the season W/L% for the same years. That equation {1.063 + (-.0161*6-year ave)} can be used to approximate future W/L%.

Modeling

What is needed to build a model to do that, however, are parameters yearly recruiting. Under Coach Pelini, his five recruiting classes have averaged 25.3, with a standard deviation of 3.0704. Those two data points, and the regression equation I computed above can be used in a probabilistic model to estimate future W/L%.

The results aren't encouraging.

Based on 1000 iterations, the average recruiting class is (not shockingly) 25.23 (as it should be based on the model). The average estimated W/L% is .58.

The best recruiting class is estimated at 21.51, and the best season W/L% is .68.

The worst estimated recruiting class is estimated at 29.54, and the worst season is estimated at .47.

WhatIf Scenarios

If, going forward, Pelini can average a recruiting class of 20.0, the model predicts that the average W/L% is .72, best is .84, and worst is .61.

If, going forward, Pelini can average a recruiting class of 15.0, the model predicts that the average W/L% is .86, best is .97, and worst is .67.

Conversely, If Pelini averages a recruiting class of 20.0, the model predicts that the average W/L% is .46, best is .56, and worst is .35.

Conclusion

I disagree with Brandon that NU is well-positioned in recruiting. Even if my model understimates W/L% by 10% (roughly 1 game per year), that still means an average W/L% of about .70. I don't think that will be good enough for Husker fans. Pelini has to improve and sustain Nebraska's recruiting significantly if he is going to keep his job.