May 1, 2012

Hardy: Why Plesius deserves a better ranking

In its most recent rankings of draft eligible players, the CFL Scouting Bureau ranks Frédéric Plesius – a Linebacker from Laval University – as the fifth most attractive prospect.  

However, based on his performance at the CFL Evaluation Camp presented by Reebok in early March, I believe a higher ranking for Plesius is justified.  

As you likely know, CFL Evaluation Camp puts draft hopefuls through a number of individual tests.  Among these tests are a bench press, 40-yard dash, vertical jump, broad jump and shuttle.  

Based on the results of these tests, Plesius should be ranked higher than fifth. Let me explain:

Since 2006, a total of 311 players have participated in E-Camp (not including kickers and quarterbacks, who have been excluded from this analysis).

Most – but not all – of these players participated in all E-Camp tests, providing a basis to rank their performance.  In other words, a player who ran the 40-yard dash in 4.45 seconds ranks higher than another player who ran it in 4.62 seconds.

Comparing Apples to Oranges: Standardizing Data

Now, it’s probably not very fair to compare the 40-yard times of a receiver to the 40-yard times of an offensive lineman.  It’s kind of like comparing apples and oranges.  That’s okay, because a statistical method known as “standardization” allows us to convert the 40-yard times of all positions so that they are comparable, so long as the 40-yard times are distributed “normally”. 

A “normal” distribution looks like a bell curve.  For example, the distribution of receiver 40-yard dash times from 2006 to 2012 looks like this: 

Every normal distribution can be defined by its mean (about 4.7 seconds for receivers) and its standard deviation (about .15 for receivers).  

What the normal distribution implies is that most observations of any given “experiment” tend to settle around an average, or “mean”, and there will be gradually fewer observations as you move further from the mean.  

In the case of receivers above, most 40-yard dash times tend to be around 4.7 seconds, with a few of 4.4 seconds and less, and a few of 5.0 seconds and more.

Having assured ourselves that the data for E-Camp results are normally distributed, one can perform a calculation (using the mean and standard deviation for each position’s test results) that converts the test results for each position represented at E-Camp to a single, standard measurement.  The calculation is performed using the following formula:
The Rankings

So, what does this all mean for Frederic Plesius? Well, having performed the necessary calculations to standardize the E-Camp data, as described above, I was then in a position to rank player performance. 

The best performance at Evaluation Camp in recent history belonged to Michael Montoya in 2010.  Incidentally, Montoya, a Running Back from Wilfrid Laurier University, was never drafted, despite producing the top marks of the entire class.

For his part, Plesius registered the following ranks:

Test Rank (out of 311)
Bench Press 35
40-yard Dash 13
Vertical Jump 19
Broad Jump 329
Shuttle 231
Total 627

Of the top 15 Players ranked by the CFL Scouting Bureau (11 of which attended Evaluation Camp), Plesius’s performance was the best.

The Importance of Evaluation Camp in the Draft Decision

I suppose you may be thinking that the example of Montoya demonstrates that CFL general managers and scouts are looking at other skills that are not tested at Evaluation Camp. 

However, we have clear statistical evidence that the majority of tests conducted at Evaluation Camp do, in fact, impact the draft decision. In other words, the athletes that test better at Evaluation Camp are more likely to be drafted.

Allow me to explain:

The “pool” of all Players that have attended E-Camp can be separated into two groups: those that were drafted and those that weren’t.

Each of these two groups is defined by the individual performances on the Evaluation Camp tests.  By compiling and comparing these results, we can determine (with a predetermined amount of confidence, known as the “confidence” interval) whether these groups are different.  

The statistical test performed to answer this question is known as a Two-Sample T-test.

For each of the Evaluation Camp tests we used in our analysis – the Bench Press, 40-yard Dash, Vertical Jump, Broad Jump and Shuttle – the results of the drafted group were significantly different than those of the undrafted group.  That is – Evaluation Camp results matter.  

And Frédéric Plesius performed better than any of the other top CFL prospects.