Can athletic testing really predict an NFL Draft prospect’s success?

Every year when the NFL Combine rolls around, fans and pundits alike analyze each NFL Draft prospect’s athletic testing numbers. How much do these numbers matter?

Back during the 2018 NFL Combine, current Kansas City Chiefs and former Baltimore Ravens offensive lineman, Orlando Brown Jr., had a performance that Bleacher Report dubbed as “the worst in the history of the event.” Every year during the pre-draft process, the NFL Combine is held and players demonstrate their pre-draft athletic measurables, through a series of tests that hope to predict NFL upside.

Brown’s athletic testing numbers were historically bad. His 40-yard dash time was 5.85 seconds, his vertical jump was 19.5 inches, and his broad jump was just 82 inches: all these numbers were dead last among every prospect attending the combine. Before this catastrophic performance, Brown was considered to be a first-round prospect, but he ended up being drafted fairly deep into the third round, at pick 83.

Many teams clearly thought that even with an otherwise standout career at Oklahoma, where Brown was a two-time Big 12 offensive lineman of the Year, this testing performance would be, at least to some extent, predictive of his career trajectory. After two years of Pro Bowl recognition in his first three years, it does not seem that Brown’s athletic testing at the NFL combine has held him back.

What we know about testing numbers for NFL Draft prospects

Obviously, this is one anecdote, and Orlando Brown’s story may be an anomaly. There is a multitude of different factors that contribute to a player’s success. I want to shed some light on how 40-yard dash time, one of the most heavily scrutinized athletic tests at the Combine, can predict future performance for running backs.

The following data consists of offensive statistics for each offensive player that registered stats each season from 1999-2013. All credit goes to Tableau Public for scraping the data from pro-football-reference.

40-yard dash time is especially studied when it comes to running backs. These times provide a clear and normalized number that measures the prospect’s speed and acceleration ability, both skills that contribute to a successful running back.

The graphs linked from the following tweet are derived from the data. It shows the relationship between 40-yard dash time and certain rushing statistical outcomes: yards per carry, total yards, and touchdowns all in a single season. Each dot represents an individual player’s single season’s stats from the years 1999-2013 with a minimum of 100 carries per season. Thus, if an individual played 5 seasons within this time, with 100 rushing attempts in each of those seasons, he will have 5-individual dots on the chart.

The correlation between 40-yard dash and running back success

There is somewhat of a loose correlation between 40-yard dash time and statistical outcomes. The faster the 40 times, the more yards, yards per carry, and touchdowns, players will be predicted to have during a certain season, but there is still a lot of variation. Obviously, this is one athletic test, for just one position, but it provides a window into how many different factors can affect a player’s season.

First, this variation may have partially come from the natural cycles within players’ careers. Some of these players may not as yet have entered their primes or may have been past their prime, but there are many other considerations that can affect the trajectory of a player’s career as well.

Perhaps, a running back has some ability (i.e. instincts, feel and vision) that cannot be captured by athletic testing, but only by the film. Additionally, some players may put varying levels of effort into their craft, which also cannot be captured by athletic testing. Lastly, some players just have better luck: they were put in better situations with better coaching, or offensive linemen to block for them, or maybe they just got lucky with injuries.

Athletic testing is something to seriously consider in the pre-draft process, but it is one of many components needed to fully evaluate a player’s potential. That is why the process is so comprehensive, as NFL teams always consider film grades, college production, and interviews in their evaluations.

Even then, teams and analysts with holistic approaches make mistakes with their prognostications. In conclusion, if your favorite team drafts a player with a slow 40-time or 3-cone drill, it’s not necessarily a death sentence for that player’s career.