I have wanted to explore this topic more in-depth. Part of the impetus for this post comes from Dave Hudson's outstanding post on this topic at Football Study Hall. Another portion of my interest in this topic can be attributed to basketball and how Dean Oliver has made it possible to measure tempo by estimating the number of possessions played.
Drive-based statistics provide essential insight into team performance. Football cannot accurately measure tempo simply by accounting for the number of drives or non-offensive possessions played during the course of a game. FYI, I distinguish between drives and possessions. By my definition, the offense must run at least one play to classify a possession as a drive. All drives are possessions. Not all possessions are drives.
Why can't tempo be accurately measured by using the number of possessions in a game?
The answer to this question is surprisingly simple. A game played by two slow-paced with multiple three and outs will have a high number of possessions. Conversely, a game played with two up-tempo teams and very few explosive plays may not have as many possessions because each offense needs to run many plays before they can score.
Here is the formula I'm using to measure tempo:
- Tempo = (Plays / Total Seconds of Offensive Possession) * 1800
- I'm multiplying this by 1800 because it equals thirty minutes. I'm using thirty minutes because the average time of possession hovers around the thirty minute mark. (Link) The number of plays run over thirty minutes effectively conveys the difference in tempo over an extended period of time.
- This only accounts for plays on statistically significant drives.
- Time of possession is not measured in overtime. The statistics accumulated during overtime must be discarded.
Please understand this measurement is imperfect. College football scorekeepers do not always accurately measure time of possession.
Here are what these numbers look like when grouping together teams by conference affiliation: