Competitive balance is generally a pretty important aspect in sports. The NBA wasn’t very fun, at least to me, during the late-2010’s as the Golden State Warriors were pretty much chalked into the NBA Championship barring any injuries. Meanwhile, the NHL Playoffs always seems to be thrilling, as the lower-seeded teams seem to all have a shot at taking home the Cup. Anyways, this got me asking the question – what is the most competitive professional sports league in the United States?

### Methodology

There are a variety of different ways that we could tackle this problem. I decided to focus on two metrics for the simple reason that the data is readily available and easy to analyze.

The first method is to do an analysis of the my own ratings against the mean. My ratings have a property where the mean of all teams within a sport is always zero. By taking the average of every team against the mean, we could then judge competitiveness. Sports with a wider margin are less competitive and vice versa. The second method is to analyze no the no-vig lines for all games within each sport. By converting the no-vig lines to probabilities, we would then evaluate how close each game is to 50% (perfectly even competition).

Using two methods instead of one will give us more confidence in the final result. In the end, we will see how well these things match up.

### Analysis

The analysis is being done on six leagues: MLB, NBA, NHL, NFL, MLS, and WNBA. Using last year’s results (with the exception of NHL where we used 2019-2020), we compiled the data. First, we looked at the data with the first method.

The results were a little interesting. The NFL, with perhaps the strictest competitive balance rules of the six, came out as the least competitive league. Meanwhile, Major League Baseball, with no salary cap, comes in right behind Major League Soccer.

For our next method, we left out Major League Soccer as three-way lines make things more complicated. We didn’t want to do an apples to oranges comparison, and thus, stuck with the other five sports.

The results from the second method look very similar to the first method, but they are slightly different. What we see is that there are two tiers of competitiveness. Major League Soccer, the National Hockey League and Major League Baseball all have a similar level of competitiveness. Meanwhile, the National Football League, NBA and WNBA are in a tier that is a less competitive by a pretty wide margin.