Wins across the National League and American League aren’t distributed equally. Looking at both current wins and our projected expected wins, the NL has more teams at the extreme ends of the wins spectrum, while the AL is more tightly grouped. The shape of the win distribution is useful because it can create a picture of the league. The AL has 20 more interleague wins than the NL due to the 140-120 AL-NL interleague record, so the AL’s distribution is shifted slightly higher than the NL’s. But the NL’s distribution is more spread out with more teams having either really good records or really poor records. Interestingly enough, one division, the National League Central, has the top three teams, Cardinals, Pirates and Cubs, in its league.

There isn’t too much difference between current and projected expected win box plots, but it’s scaled to a more familiar end-of-season win total.

These plots loosely imply there is more parity in the AL, but only in the sense that inequality is measured by single-season wins. Using the gini coefficient, an economic metric which was discussed at SaberSeminar during Bill Petti’s performance consistency presentation, we can measure the inequality within the two leagues and compare. The higher the gini coefficient the more inequality there is. The NL has a gini coefficient of 0.089 while the AL has less inequality with a 0.050 gini coefficient.

Finally, the Cubs, the projected second National League Wild Card team, are projected to have 94 wins, while the Angels (the American League counterpart) are projected to have 12 fewer wins.