This post attempts to use some statistics, figures and plots to assess team performance against college football spreads.
The histogram of season performance of teams against the spread for college football for seasons 2014-2018 [1] is a normal distribution with x% of teams season performance between 25% and 75% [2].
To see whether a team’s season performance vs the spread carries from one season to the next, the visual below shows the current and prior year performance vs the spread as a scatter plot. No pattern emerges, with 43% of teams declining year over year and 45% of teams improving year over year. The remaining 8% were constant year over year.
Looking at the same data differently, the next visual places each team into a quadrant based 50% as the divider. Counting each data point as a percentage of the population, we see that only 13% of teams with a better than 50% performance against the spread in one year perform better than 50% the next year. Additionally, a team with a performance of better than 50% performance in a year is much more likely to under perform the next year than continue a over 50% performance.
Statistics / Notes
[1] Each data point is a teams season performance against the spread calculated as a percent (games covering spread / total games). In the 2014-2018 timeframe there are 708 teams in the population with at minimum 10 games that included a spread in the season.
[2] In the population 708 games, 673 had a season performance of between 25% and 75%.
Gamblers Analytics 