Why underdogs do better in the NFL than the UIL

    During last years 6A playoffs, 30% of first round games were won by lower seeded teams. Compare that to the NFL, where four of the six wild card round games were won by teams with lower seeds. Of course there are differences between UIL Football and NFL Football, but what exactly are those differences doing to impact the differences between skill and luck in their respective leagues. 

Michael Mauboussin wrote the book The Success Equation, which studied the difference between skill and luck in different sports leagues. I won't go into detail about how he did that, there will be another post for that, but I will try to explain it as basic as I can; By measuring the variance in win/loss records in a league, and by measuring the variance if the league was 100% luck based, you could use those numbers to find out how much skill the league is based on. He studied the four big American sports leagues plus the premier league, and found that the NHL had the highest amount of luck contributing to a teams win/loss record, 53%. Meanwhile, the NBA had the lowest amount of luck contributing to their win/loss record, 12%. The NFL was the 2nd luckiest league in the group, 38% of their win/loss records were contributed to luck. 

This doesn't mean that NHL players are less skilled than NBA players, but rather the NBA does a better job of reflecting a teams true skill than the NHL.

To compare the NFL to UIL football, we need to first look at the differences between the leagues. Obvious ones include the skill depth of the players, players in the NFL are going to be much closer together in skill because they're the best football players from across the country. In high school football, you're only competing with local players for your spot. In the NFL, it's the job of the players to play football and to be their best. High school players don't have that luxury, so the differences in skill gets wider. 

In order to find the percentage of wins or losses by a high school football team that we can attribute to skill and luck, we need to find the variance of the teams win/loss records. I'll be using data from the 2019 season, since 2020 is going to give us a bad set of data to measure luck because of the coronavirus. As well, it's better to use data where all teams play the same amount of games. I'm only using games where a 6A or 5A team competed, since thats the data I have ready to use for this. The variance comes out to 0.097, which might not mean anything now but we will use that to calculate skill and luck in UIL football.

After calculating that, I can calculate what the variance would be in an all-luck league. Imagine if the two teams walked onto the field, flipped a coin to see who won, and then went home. That is what this would be like. The score changes for each league and sport, because it depends on the number of competitors and number of games in a season. The results based on skill will go up for sports with more than two competitors in a single match or game, such as in swimming or track. The second part of this formula, number of games, will also increase skill as the number of games increases. Ultimately, the percent of results based on skill in UIL Football comes out to 74%. The 14% difference between the NFL and UIL is probably because of the difference in skill between the players in each league. One factor that closes this gap is the difference in the number of games. While an NFL team plays 16 regular season games (soon to be 17), UIL teams only play ten games. If the UIL expanded the regular season to 12 games, that would increase the amount of wins based on skill to 79%. 

A common mistake people make is assuming that one team is better than another because they beat them in a game. While it's true most of the time, we also need to consider how luck could've affected a games result. Especially with the 2020 season, consider how a player or coaches quarantine might've affected the teams overall quality and thus changed the outcome of the game.