The general consensus is that the AL is much stronger than the NL. It’s also assumed that the top AL teams are all much stronger than the top NL teams. That may be true. But there are a few data points that might indicate it’s not quite as simple as all that.
The AL boasts 3 teams with 100 or more wins, (Boston 108, Houston 103, and New York 100) and the top 4 teams overall in terms of Wins/Win %
BUT, the AL also boasts three 100 loss teams (Baltimore 115, Kansas City 104, Chicago White Sox 100)
So are the top records in the AL due to having the worst teams in baseball to beat up on, or are the top AL teams so good that the lesser AL teams don’t stand a chance ?
Interleague Records give us a clue:
NL leads AL 158-142 (1330 runs to 1254)
Interleague records are the largest sample size we have to compare the leagues. Typically the AL has the edge here. Interleague records are often mentioned as supporting evidence when the topic of league strength is mentioned. So this year’s results may be an indication of a leveling perhaps.
However, if we look at the playoff teams, here is how they shape up:
So here you see among the very best teams in baseball, the AL has a 50 point Win % advantage in Interleague play. If you take out the Red Sox , the balance 4 AL playoff teams combined for a .600 W%, almost the same as the NL playoff teams.
Scoping out a bit, my intuitive sense tells me that the Red Sox and the Astros really are superior teams to any team in the NL. The Astros Pythagorean W/L is 109-53, they are the defending world champions, and truly have a great team. The Red Sox have been almost unbeatable, but their Pythag is a little below their season record, (103 vs 108).
The Yankees ran up their record somewhat against the Orioles, (12-7) and the Blue Jays (13-6). The Indians had the advantage of having 3 of the worst teams in baseball, (Royals, White Sox and Tigers) in their division.
Meanwhile the Brewers, Rockies and Dodgers all put up good interleague records, as did the Cubs, even though they are out now.
There is probably a little more parity in the NL, and the top AL teams are probably stronger, but the gap may not be QUITE as big as some thought. Astros/Red Sox ALCS may ultimately be a matchup of the two best teams in baseball, but I would look for whatever NL team that emerges to give the AL a good fight.