What is predictability in sports? It’s a measure of how close things fit to any given system of estimating results before they happen. For a basic example, consider the sportsbooks’ favorite in each match. If they won every time over the season, the league would be 100% predictable for that metric. Obviously, real life is more messy and complicated than that example, but which sports are thus the most predictable? And, why?
This article will look at the key stats behind several different major sports leagues to assess their predictability. That will be across the whole season, in individual matches and even in terms of multiple season or title dominance. A highly predictable league will see the favorites win more often and the same teams win year after year, and an unpredictable one would be full of upset results.
How to Judge Predictability on a Simple Level
Although answering this question completely would require in-depth analyses of datasets, there are some simple metrics that can, on the most basic level, help assess a sports league’s predictability.
One is bookmaker accuracy. Once sportsbooks crunch the numbers, it’s their business to be as accurate as possible. And you can see these numbers any day, any time. The more the sportsbooks’ favorites win every week, the more predictable a sports league is. Simple.
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High scoring sports tend to average out as more predictable, as there are more chances for the top teams to dominate. For example, its easier for a soccer team to sneak a 0-1 away win against better opposition because keeping the opponents to zero goals is a lot easier in soccer than basketball or American football.
Big American Sports are Among the Most Predictable
So – given all that, which sports are the most predictable? Well, the major American sports leagues are certainly up there. The NBA, the NFL and MLB are all data-rich sports with a lot of stats to digest, many games in a season and a lot of high scoring matches. Although upset results do still happen this all adds up to high predictability in many cases.
In the NBA, the favorites win more than 65% of the time. Which is statistically very significant. Basketball is a very high scoring sport with smaller teams, so superstar players can absolutely dominate whole games basically by themselves. Meaning if a team can pull in three or four franchise players at once, they can crush the league multiple years in a row in a way that doesn’t happen as often in other sports.
The NFL is another interesting case. In the 24/25 NFL season, the sportsbooks’ favorites won more than 70% of the time. This has been a rising trend for several years now in the NFL – at a time when the Kansas City Chiefs were in five out of the last six Super Bowls and won four of them. The league is already considering ways to make games less predictable, potentially by expanding the season or mixing up some of the conferences. The MLB, on the other hand, is far less predictable on a game by game basis – but over a 162 game season the long-term outcomes are more predictable based on team strength.
European Soccer Leagues are Less So (But Becoming More Predictable)
Two sports that are much less predictable are soccer, or football to a global audience, and ice hockey. A keen sports viewer will be able to tell from this almost immediately one of the big differences that sets these two sports apart from the three American leagues above. That is, goalkeepers.
Any sport with a dedicated goalkeeper, makes scoring harder and therefore games have a lot more variance. When a team can score one lucky goal and then hold out defensively against better opposition – the chances of the favorites winning every week goes down considerably.
In fact, research has proven that if you bet on the sportsbooks’ favorite to win in every match of every game in Europe’s top five soccer leagues between 2015 and 2019, only one league (Italy’s Serie A) would have won you money over the long term. However, both the NFL and the NBA would have been profitable following a similar method.
The regular nature of draws in low scoring sports also throws a spanner in the works for the favorites’ winning chances. It’s very rare for matches to result in a tie in basketball or the NFL – usually only one or two per season – meaning a favorite victory is always more likely. In the English Premier League however, 25% of matches in the 24/25 season ended in a draw.
