Using Betting Line Movement for Against-the-Spread College Football Predictions
How accurate are college football predictions that are based on betting line movement? For sports bettors in general, and college football bettors specifically, the movement of the point spread (the betting line) from where it opened to where it appears to be headed is considered important enough to note by virtually every college football betting analyst or handicapper. The value or significance attached to that line movement varies, but its ubiquity in college football betting conversations warrants an examination. This article is intended to summarize the results of that examination conducted by our analysis here at CollegeFootballWinning.com. The college football predictions in question are those against-the-spread.
Line Movement Defined
For the purposes of our investigation into the predictive power of line movement, we used opening and closing betting lines (point spreads) to see how often that direction (from opening to closing point spread) indicated the correct against-the-spread outcome. Consider the following example: For the 2015 College Football National Championship game, Oregon opened as a 7.5-point favorite and closed as a 6-point favorite over Ohio State. Since the line movement amounted to Oregon becoming less of a favorite, the line movement indication was that Ohio State was the correct betting side. Ohio State won the game outright (and covered the spread by 28 points). Therefore, using our parlance, the “line movement indicated the correct side” in that matchup.
Betting Line Movement Facts
For the past 10 college football seasons (from 2005-2014), the closing betting line differed from the opening betting line in over 87% of all college football games. Examining this most recent season (2014-2015), that figure was up to 90.32%, so it should be understood that most college football betting lines do not end up where they began. It was, therefore, necessary to exclude from our study all games that opened and closed at the same point spread (even though many of those lines “jumped-around” between their opening and closing positions).
Looking to betting line movement for college football predictions over the past 10 seasons reveals that line movement indicated the correct side 49.34% of the time. The graph below illustrates, by year and percentage, the accuracy of college football predictions (against-the-spread) as indicated by line movement:
Based on 10 years of college football betting data, betting line movement was not a good indicator of against-the-spread outcomes. For the statistically-inclined, the average accuracy of predicting college football against-the-spread outcomes through line movement in each of the past 10 seasons is within one standard deviation of the mean. Generically using line movement for college football predictions appears to be no help whatsoever. Consequently, the college football betting world might do well to refrain from using general betting line movement as a justification for taking a position on a college football side.
[For a similar study done with Totals (instead of point spreads), CLICK HERE.]