Wednesday, February 29, 2012

The Harvard Sports Analysis Collective

I came upon this looking for the TRUE value of the Ram's #2 pick in the 2012 NFL Draft. I'm gonna go with the Harvard guy Kevin Meers! You can go straight to the article by clicking the link below.

Taking data from, I have created a much better system that more accurately values each pick in the NFL draft, similar to the work done by Chase Stuart. Pro-Football-Reference uses a metric called Career Approximate Value (CAV) that allows one to compare players across seasons and positions. It is not meant as the ultimate NFL statistic. It is useful for comparing large groups of players across time and positions, which is exactly the objective here. Using data from 1980 through 2005, I analyzed each overall draft pick from 1 to 224 (the 32nd pick of the 7th round in today’s draft). I found the mean, median, and standard deviation of the CAV for each pick from those 25 years, creating one set of data that represented the historical value of each pick. I then found the mean, median and standard deviation for this new dataset to determine the expected value of a normal draft pick. I then used that normal pick to standardize my data, finding the percentage value over average, or Career Approximate Value Over Average (CAVOA), for every pick in the draft.

For example, the first overall pick, historically, has had a mean CAV of 66.7. The standard draft pick had a mean CAV of 15.03. . Thus the first overall pick was 443.39% more valuable than the standard pick. Using this method, I found the CAVOA of every pick in the draft, and then regressed it against overall pick number. The regression equation was with an R2 of 0.91599. The R2 means that the variance in overall pick number explains 91.599% of the variance in CAVOA. Using this equation, I found the expected CAVOA for every pick in the draft.

The CAVOA is the comparative value of each pick versus the normal pick and is based off of real, historical, on-field performance. This non-arbitrary statistic is a massive improvement over the old draft chart. To compare my system with the old one, I transformed the old system into a percentage over average as well. The results are below.

The old system massively over values the earliest picks and significantly undervalues mid-to-late round picks. The regression line is clearly a better predictor of future value than the old chart.

No comments: