Recruiting services evaluation. Stacking them up.

I recently looked at how each of the recruiting services has performed in terms of NFL draft status as a measure of success. That analysis is here:

Here, I looked at each of them in turn in terms of how predictive they are of on-field success. As I have already found, recruiting and winning is generally non-linear, especially once you start including teams without much a blue-chip percentage.

I used Rivals, ESPN, 247, and the Composite recruiting class ranking data from 2017 through 2019. I took the average ranking for the top 100 teams for those 3 years. Teams that averaged outside of the top 25 were dropped.

Using a simple linear regression to determine how much of 2019 win % was predicted by average recruiting ranking. The services didn't exactly reach the same levels of accuracy for 2019.

Service Accuracy

Composite 74.6%

247 72.0%

ESPN 71.6%

Rivals 63.7%

The above table is the overall accuracy of each service. This statistic is the correlation between each service's average 3-year class ranking and that team's on-field win % in 2019. When combining all 4 services into one aggregate "service", the accuracy is 74.3%, so still not as good as the composite here. Other insightful statistics such as effect size, standard error, and confidence intervals were all better for the composite (than the aggregate) by very slim and insignificant margins.

When plotted, the aggregate looks like this:

Scatter plot: All Services

Table of outputs:

Table of outputs

And count of teams by conference:

Count of Teams by Conference

Ultimately, ESPN was the worse at picking which high school players would get drafted, but (for 2019 at least) Rivals was the worst at ranking classes that predicted winning.

If you're interested in the full breakdown, it is located here:

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