When evaluating and comparing player speed based on 40 yard dash times, it is important to keep in mind that the 40 yard dash time recorded at scouting combine and pro day events is not truly “official” as in completely correct. Timing methods vary, but most involve at least one manual process performed by a human and thus prone to error. In addition to being slightly inaccurate because of human involvement, there is not an established standard on how 40 yard dash times at the NFL Combine are reported.

A popular belief held by many casual NFL fans is that players at the NFL Combine run the forty yard dash once, it is timed electronically, and since it was timed electronically then that 40 time can be regarded as official. All of these are misconceptions. The facts below describe in detail how the process of recording a 40 yard dash at the NFL Combine really works:

Each participant is given 2 attempts at the 40 yard dash and is timed with 3 different stopwatches on each run, however only one of those stopwatches is “electronic.” The electronic timing is not fully electronic. The stopwatch is started by a human, and it is important to understand that it is started by human hands on the first movement of the 40 yard dash participant. That means that there is always room for human error, though less than if it were fully hand-timed. Since each player runs the 40 twice, there would be no single “official” time even if only the electronic times are used.

You may notice that different sources of NFL Scouting Combine data report slightly different 40 yard dash times. For example, the NFL.com website combine data reports different 40 times than NFL Combine Results, which are both different from other sources providing 40 yard dash times. This discrepancy is because of the differences in how 40 yard dash times are reported.

The fact that each participant has 6 “officially” recorded 40 times (4 manual, 2 electronic) explains why reports of 40 times vary depending on which scouts you ask. Some scouts may use an average of all 6 times and report that. Other scouts may use an average of only the 2 electronic times, throw out the fastest and slowest time and average the remaining 4, or use a more complex method of coming to a single number. The point is that most scouts use different methods of arriving at a single 40 time, and that is responsible for the discrepancy amongst “official” 40 yard dash times.

As a result of all of these factors, it is very difficult to establish a consensus “official” 40 yard dash time for a particular player or for the sake of NFL Combine all-time records. NFL Combine Results believes that the most important thing for the sake of accurate comparison is to consistently use the same method of determining a single 40 time, and it is also our opinion that the best method of reaching a single 40 yard dash time is to take the average of the two electronic times as they are the most likely to be the most accurate.