The inequality of the 2024 season

Translated by José M. Hernández Lagunes

In 2017, I introduced the Gini Coefficient. Well, I introduced it to some of you; others were already familiar with it. The Gini Coefficient, invented by Italian statistician Corrado Gini, calculates the inequality in a distribution. Gini created this measure to estimate income and wealth inequality. The Gini Coefficient varies between 0 (perfect equality) and 1 (perfect inequality). This is a standard app, from the Organization for Economic Cooperation and Development, a club of 38 mostly wealthy countries. Here’s the Gini Coefficient for disposable income (note to economics nerds: includes pass-through payments and taxes!), for example, income inequality:

OECD Chart: Income inequality, Gini coefficient, 0 = complete equality; 1 = complete inequality, Annual, 2021

The Gini Coefficient is almost equal to half the expected difference between the income of two random citizens. As seen in the graph, the Slovak Republic, with a 44% difference, was the most equal, followed by Slovenia and Belgium, both below 50%, using the most recent data available. The most stratified nations were Costa Rica, with a difference of 97%, followed by Mexico with 84% and Türkiye with 83%. The United States, with 75%, is in fifth place, with its inequality slowly but consistently decreasing over the years.

(The data is up to 2021. Yes, I know it is old data; the OECD is updating its data and this is the most recent distribution available. In the limited data available for 2022USA ranks fourth among only 10 countries).

In the article linked at the beginning, I used the Gini Coefficient to measure the inequality among major league players between hitting home runs and stealing bases. I imagine this is not what Gini had in mind when he invented this measure in 1912. But look, it worked, even if the application was a little off.

Here’s another app that makes a little more sense: win-loss record. Yes, it is not equal to wealth or income. But we can compare teams’ winning percentage in a given season on an equal footing, since they all have roughly the same number of games, and it’s easier to compare than a hitter’s home run total with 700. plate appearances and total of one with 70.

Seven years ago, I calculated the Gini Coefficients for each season – separately by League – from 1901 (the year the American League was created) through 2017. I have updated this analysis in 2018, 2019, 2020, 2021, 2022 and 2023. Let’s move on to 2024.

Before we show you the results, let’s have our frame of reference. In a 12-team league, if all teams finish 81-81, the Gini Coefficient is 0.00: perfect equality. If one team wins 92, another 90, another 88, etc., all the way to one that wins 70, the Gini coefficient remains pretty much the same: 0.05. If half the teams win 162-0 and the other half 0-162 (I know, it’s impossible, but humor me), the Gini is 0.50, that is, unequal, but not at the level of total inequality.

Over the past 124 years, the Gini Coefficient of leagues has ranged from a low of 0.048 to a high of 0.168.
Here is the most lopsided league in MLB history, the 1909 American League:

This is what a Gini coefficient of 0.17 looks like in baseball. The Tigers, Athletics and Red Sox accounted for nearly half of all league wins. Nobody else was good, and the Senators were bad but seriously bad.

This kind of thing happened a lot in the early years of baseball. Of the 12 most lopsided leagues since 1901—that is, among 248 league seasons—the only one after World War II is the 1954 American League (the fourth most lopsided; Cleveland won 111, New York 103, Chicago 94, and no other team won even 70).

By contrast, the only prewar year among the 22 most even seasons, according to Gini, was the 1915 National League, diminished by the Federal League (which dissolved after the season).

The most even league in history was only nine years ago:

Of course, that’s not how it worked in the American League in 2015. There were three divisions, and the Royals won theirs by 12 games and the Jays by 6. But the League as a whole…those teams were pretty close. The difference between the first and fifteenth teams in 2015 was smaller than the distance between the first and sixth teams in the most lopsided American League season of all time 1909. The Gini Coefficient for the 2015 American League was 0.048. The 1974 and 2015 American League seasons, along with the 1915, 1968, and 1983 National League seasons, are the only league seasons with a Gini Coefficient less than 0.05.

Where does the recently completed 2024 season stand? For one thing, there were no 100-win teams for the first time in a decade. The World Series was contested between two teams that were obviously the best in their leagues and equally flawed. That suggests a narrow gap between the teams. On the other hand, the Angels lost 99, the Marlins lost 100, the Rockies lost 101 and the White Sox were the eighth most dominated team of all time. Even if there were no super teams at the top, there were some terrible ones at the bottom.

The Gini coefficient for winning and losing percentages in the American League was 0.085. In the National League it was 0.075. The American League figure was the lowest since 2017. Those ranges are quite low historically, although AL inequality is still above average if we limit ourselves to the most recent seasons.

• In the 248 League seasons since 1901, American League inequality was the 144th highest in history, at the 43rd percentile.
• The National League figure is 180th, in the 28th percentile.
• In the 158 League seasons since 1946 (end of World War II), the inequality of the American League was the 67th highest (58th percentile), that of the National League the 101st (37th percentile).
• In the 112 League seasons since 1969 (divisional play), the inequality of the American League ranks 37th (68th percentile), that of the National League 64th (44th percentile).

Here are the 15 most lopsided seasons of the Divisional Era:

The 1977 AL and 1993 AL were expansion years, as was 1969. (The 1998 expansion–Rays and Diamondbacks–does not make the list.) The 2020 season was, well, you know. The level of inequality we have seen several years this century is worse than most boom seasons and the year of the pandemic.

But the National League has gone from being one of the most unequal in the Divisional Era in 2021-22 to being more equal than usual the last two years. And American League inequality fell sharply in 2024. Inequality in baseball is more volatile than national income, but we appear to be trending away from recent peaks. Perhaps we are seeing more competitive balance, parity or mediocrity, depending on how you look at it. That said, the lack of variance in the 2015 American League seems like a long, long time ago.