Inside The Numbers: Power Ratings Recently, message board poster "Technocrat" emailed me a spreadsheet he had been working on that was pretty interesting. Technocrat had devised a way to calculate power ratings for Virginia Tech football players based on their height, weight, and 40yard dash times. I took a look at his spreadsheet, gussied it up, and the next thing you know … voila! Another "Inside the Numbers" article was well under way. When you say "power rating" to your typical football fan, it will bring up many different connotations in everyone's minds. You can build a power rating formula that is as simple or as complex as you want it to be. Technocrat's power rating is pretty simple, from the standpoint that it only requires three points of data as input: height, weight, and 40 time. I suppose you could complicate this thing massively by taking into account weightlifting numbers, vertical leap, shuttle times, etc., but with the deadline pressures facing each issue of the TSL Extra, I took Technocrat's basic formulas and ran with them. He and I both freely admit that you may or may not agree with his system of measurement and calculation, but "Inside the Numbers" was never really intended to be the definitive answer to statistical measurements. I prefer to think of "Inside the Numbers" as being a statistical jumpingoff point and a conversation starter more than anything else. What follows is an explanation of Technocrat's formulas, and then I'll give the results so you can find out which players scored highest in his power rating system. As always, those of you who want the executive summary can skip ahead to the results (see the paragraph titled "The Numbers") to see how the players rank. The engineering and scientific types out there can muddle through the next paragraph (titled "The Formulas") on your way to "The Numbers." As is always the case with "Inside the Numbers," the results are interesting and illuminating, and you can learn a lot about the VT football players just from examining the numbers. The Formulas Okay, try not to glaze over here…if the technical stuff puts you to sleep, you can jump right ahead to the next section ("The Numbers"). Technocrat's power rating formula is simple. He calculates a mass component and divides it by a speed component to give his final power rating. So if a player's mass component is 180.0 and their speed component is 60.0, their final power rating is 180/60 = 3.000. The speed component is created by squaring a player's 40yard dash time and then multiplying by a "speed weighting" factor, which I'll describe later:
To derive the mass component of the power ratings equation, you must first calculate a player's Body Mass Index (BMI). BMI is calculated by converting the player's weight to kilograms (divide pounds by 2.2 kilos/pound) and their height to meters (divide total inches in height by 39.37 inches/meter). You then divide weight (in kilos) by height (in meters) squared, and this gives you the player's BMI:
By the way, Technocrat didn't just make BMI up. Go to yahoo.com or your favorite search engine and do a search on "body mass index" and you'll get at least one link to the formula shown above. To get the mass component of the power rating, you multiply the BMI by a "mass weighting factor."
Lastly, to get the final power rating for the player, you divide the mass component by the speed component:
So what are the "speed weighting factor" and the "mass weighting factor"? They are numbers that you use to assign more "weight" to either the mass part of the equation or the speed part of the equation. So if your mass weighting factor is 2 and your speed weighting factor is 1, that doubles a player's power rating over a 1:1 ratio. Likewise, a mass weighting factor of 1 and a speed weighting factor of 2 cuts the player's power rating into half that of a 1:1 ratio. Note that changing the weighting factors does not alter how the players rank relative to one another, because they're just multipliers. If you change them, they affect all players' ratings proportionately. So if player A has a higher power rating than player B, his rating will remain higher no matter what you do with the weighting numbers. The original spreadsheet that Technocrat sent to me had a masstospeed ratio of 5 to 3, so he chose to give more weight to the mass portion of the equation. That's fine with me, and as I mentioned, it doesn't affect how they rank with respect to one another. So let's start crunching some numbers! The Numbers Again, this formula only has three input variables: height, weight, and 40 time. All of the data for the spreadsheet that Technocrat sent to me were taken from "Gentry's Iron Palace" on BeamerBall.com, and the numbers are from the most recent winter/spring testing sessions. Of course, some players were out with injuries and were not able to test, so the figures entered for those players were the most recent ones available (in most cases, fall of 2000). This information is also available on BeamerBall.com. Technocrat did all the research and entered all of the data into the spreadsheet before sending it to me, so any errors in data entry can be attributed to him (I love being able to blame it on the other guy). Having said all that (drum roll, please), here are the power ratings for the top 15 players on Virginia Tech's spring football roster:
Cols Colas's appearance at the top of the list is no surprise to anyone who has been following Tech football closely this spring. Colas was, in my opinion, the weakest of Tech's four primary defensive ends last year (Colas, Lamar Cobb, Nathaniel Adibi, and Jim Davis). But from the comments the Virginia Tech coaches are making to the press, Colas has been a madman this spring. He posted great numbers in the weight room (he is the only Super Iron Hokie amongst the defensive ends) and has really come on strong on the field and in practice, seriously threatening starter Lamar Cobb at the "Stud End" defensive end spot, which is Corey Moore's old position. To explain the "Super Iron Hokie" classification for those not familiar with Mike Gentry's strength and conditioning program at Virginia Tech, this is one of six classifications that Gentry gives his athletes according to their weightlifting capabilities. Depending upon a player's overall weightlifting performance, Gentry will classify a player in increasing levels of achievement as a Maroon Hokie, Orange Hokie, Hokie, Iron Hokie, or Super Iron Hokie. The weightlifting requirements for reaching each level are different for each position, but they are clearly defined. The classification of Super Iron Hokie is very hard to achieve. There are only 13 Super Iron Hokies among the players who were able to lift this spring, including walkons. But beyond the Super Iron Hokie classification, there is another level, the Super Iron Elite Hokie, also known simply as the "Elite" Hokie. There is only one of these: fullback Jarrett Ferguson, who lands at #3 on our list. At #2, fullback Wayne Briggs heads up a list of six running backs that reside in the top 15 of the power ratings, including four fullbacks. Tech's tailbacks and fullbacks are phenomenal athletes, with 6 of the 10 running backs reaching Super Iron Hokie status, and one of them (Ferguson), attaining the coveted "Super Iron Elite Hokie" status. The ratio of 7 out of 10 athletes at a position being Super Iron or above is a remarkable percentage, and fully half of the Tech's 14 athletes at those two classifications are running backs. It is therefore no surprise to see so many tailbacks and fullbacks on this power rating list. At #4 is Vegas Robinson, who has also made a name for himself in Mike Gentry's strength and conditioning program. Vegas is one of only 3 Super Iron Hokies among Tech's 13 linebackers. #5 and #6 in the power ratings are David Pugh and Kevin Lewis. They are 2 of the 5 defensive tackles to appear in the top 15 of the power ratings. Pugh and Lewis are great athletes, but the key is, they can move their big bodies (271 and 281 pounds) fast (4.69 and 4.89 seconds in the forty). Anyone who is 61, like Pugh and Lewis, over 270 pounds, and who runs a sub5.0 forty time will make this list. #7 is Keith Burnell, and then at #8 is Larry Austin, the only defensive back in the top 15. Larry's presence here is due mostly to his blazingly fast 40 time of 4.26, recorded in the preseason last fall. If you drop Austin's 40time to a stillfast 4.35, his power rating falls to 2.473, and he drops out of the top 15. Beyond Austin, in slots 915, are a collection of running backs and defensive linemen, including defensive end Nathaniel Adibi, the only DE other than Colas to make the top 15. Comparison with Historical Athletes Let's throw into the mix three recent football players who are generally regarded as some of most powerful athletes ever to see the football field for Tech: Michael Vick, Corey Moore, and Cory Bird. Using their numbers from the media guides for their final seasons at Tech (1999 for Moore, 2000 for Bird and Vick), all three players crack the top 15:
Michael Vick tops the QB's that are currently on the roster, of course, and Cory Bird tops the safeties that are currently on the roster. No big surprise there. The big surprise is Corey Moore finishing third in the defensive end slot, behind Colas and Adibi. Here is where the weight advantage that Colas and Adibi have over Moore really comes into play. Colas outweighs Moore by 28 pounds, and Adibi outweighs Moore by 42 pounds. Colas is nearly as fast as Moore (4.41 compared to 4.38), and Adibi is fast enough (4.55) that his weight advantage overtakes Moore's speed advantage in the power ratings. This should excite you about the potential of Colas and Adibi. If both players can continue to get stronger, learn their positions, and play with the intensity of Moore (good luck there!), they both have the chance to be very good defensive ends. Comparing Positions With the number of running backs and defensive tackles making the top 15, it naturally begs the question: how do the position averages rank in the power ratings? Here they are, from top to bottom:
This ranking of the positions by average power rating bears out what we saw in the top 15: running backs (comprised of fullbacks and tailbacks) are the top group, followed by defensive tackles and defensive ends. Closing Comments The top 15 is interesting because it includes many players who are established Hokie stars (Ferguson, Pugh, Austin, Lee Suggs, Adibi and Chad Beasley), some players who have come on strong lately (Colas, Robinson, and Burnell), and some players who have never made their mark and may never get the chance to (most notably, fullbacks Briggs, Joe Wilson, and Marvin Urquhart). So what does the power rating say? Well, it tells you who among the current players is short, heavy, and can run fast. Take a look at Channing Reed and Chad Beasley. No one is saying Reed is one of the best athletes on Tech's team (according to BeamerBall.com, he hasn't even earned Maroon Hokie honors), but because he is short (611/2), weighs 311 pounds, and can run a 5.2 forty, he comes in at #13. He's two spots ahead of #15 Chad Beasley, who is only 19 pounds lighter but nearly 0.4 seconds faster. But since Beasley is significantly taller at 65, he lands below Reed in the power ratings. In the case of some of the players, you can look at the power ratings and get excited. The comparison of Moore to Colas and Adibi is particularly interesting. But in the case of other players who have yet to bloom and may never, it might not mean much. But that's the fun of "Inside the Numbers," isn't it? Sometimes it's an exact analysis that proves a point, yet other times, it just makes you think. Next month, we'll do it all again with a different topic. The Data To see the full list of players ranked by power rating, check out this web page: http://www.techsideline.com/tslextra/issue006/powerratings.htm To download the data yourself in Microsoft Excel 97 spreadsheet format, head to this link: http://www.techsideline.com/tslextra/issue006/powerratings.xls (Rightclick the link and do a "Save Link As" or "Save Target As" to save the Excel file to disk.)
