CFB Mythbusters: The Big-Win Hangover

You’ve heard it before. A team get’s a “big” win over a highly ranked opponent, or maybe an upset win as an underdog. The next week, what do the analysts all say?

“Coming off a big win last week, can they keep that same energy up and stay focused? Expect a bit of a hangover and they lose this one.”

Commenters say it so often that it almost sounds like college football folklore. But is there any weight to this “hangover effect”? Do teams actually struggle after a big win, still riding the highs of the previous week and unable to focus on the task at hand.

We looked into the numbers and found a very interesting story. There is no identifiable hangover effect. In fact, there might be a “big win boost” effect, where underdogs are shot full of confidence in themselves and start playing up to their opponents’ levels, knowing that they’ve already hung with the best of them.

Wins Breed Wins

The first thing I looked at is the difference between winning a game and losing a game. Is there even an inkling of evidence that a team might lose more often after a win? I controlled for the difficulty of matchups using the difference in Elo ratings between the two teams, and then found the average win rates in games following a win vs. games following a loss.

It turns out winning football games is a good indication of your ability to win more football games. I broke it down by the difficulty of a team’s two games, and by the result. The left orange bar shows their win rate in their second game after a loss in the first game. The right blue bar shows win rate in the second game after a first game win.

As you can see, the average win-rate in game #2 is almost always higher, sometimes by a wide margin, after a win in game #1 compared to a loss in game #1. The only decline is a negligible decline in games where you lose game #1 to an easy opponent, and then come back in the second game to perform better against a second easy opponent, but the sample size was so small that this likely amounts to rounding error.

The result that I think most “analysts” are talking about is either:

a) playing an easy game and being “sleepy” after a big win, or 

b) playing two tough opponents back to back and not being able to live up to the hype after your first win.

In both cases, teams play better after winning the first game than losing it. This is intuitive but not the common narrative. Don’t be fooled by it!

Sidenote: This also debunks the idea of a “bounceback” win after a loss, indicating that somehow by sucking one week, you will be more inspired to suck less the next week. While this may be the attitude of many teams, it doesn’t usually work out in practice. As it turns out, your next opponent could care less about your need to bounce back. You play better if you won the previous game.

Let’s look at just games where the first game was won for a moment. Controlling for the quality of your second opponent, does the “toughness” of win #1 affect your outcomes in game #2?

We would say no after looking at this. When your second opponent is a cupcake (defined as ~ 85% or more win probability), your win rate is ~ 95% whether you’re coming off a “big” win against a tough opponent (you had < 15% win probability) or another easy game.

When your second opponent is a tough matchup, you win about 12% of the time whether you’re coming off another tough win or a cupcake win. So strength of previous opponents do not affect next-game results.

Ok, before we fully debunk this myth, let’s look at one more scenario referenced above. You won in an upset win. You’re riding a high. Now you have an easy game you should win. How do you perform in this game after an upset win compared to just a normal win against an evenly matched opponent?

Remember, the game #1 result was a win, so you can only go down from here in win rate. So what is the difference in win rate in that 2nd easy matchup vs. your game #1 win?

When teams pull off an upset win, they perform slightly better against their cupcake matchup the next week than if they had just won an average game. However, these were small samples. There is no evidence of any hangover here.

Underdogs Play Better in Back-to-Back Tough Games

Take a look at this for a second. This is just the difference in win rates from one game to the next, controlled for opponent. Teams that play two games in a row where they are favored in both actually tend to struggle more in the 2nd game.

Meanwhile, underdogs actually step up and play better in game #2 than they do in game #1! This is exciting because it means those underdogs are getting better and maybe learning from game #1 struggles against similarly tough opponents.

I’d look out for any teams that have just played a tough game–win or lose–and see if they’re playing another big opponent next. They might just shock them. Similarly, I’d look for any team that is favored big in back-to-back games and maybe short them in that second game. Remember, this part has nothing to do with whether they win or lose the first game. It’s more indicative of the experience they gain in the previous game.

You can see the same thing put similarly below, but you’ll notice that most of this discrepancy is within the margin of error.

So we’ve learned a few things from this analysis:

• Teams that win games are more likely to win their next game than teams that lose (kind of the “duh” test).
• The strength of opponent in your first win does not affect the outcome of your next game. The difficulty of a game (in terms of opponent rating) has no implications on the next game.
• Big upset wins may actually slightly invigorate a team in their next game.
• In back-to-back games, teams that are favored both times tend to struggle more in their second game than teams that are underdogs twice.
• There is no evidence of any letdown/hangover after a “big” upset win.

Of course, there are a million other ways we can slice and dice this data, but I think this is a pretty decent amount of evidence against the hangover effect. Some other interesting follow-ups could be how teams play against the spread following big wins, or if the margin of victory or excitement of the game (an emotional win) has any impact on next game results.