Better to be Lucky than Good?

In 2016, the Texas Rangers went 36-10 in one-run games. Articles were written about how this was insane and unsustainable. It inspired a whole luck index at Baseball Prospectus. Indeed, in 2017 they regressed.

Now, we have the 2018 Mariners. The Mariners are 21-9 in one-run games. For this Astros’ fan, it’s “Oh no, not this again.” While The Ringer finds this charming, it has Astros’ fans shaking their heads. (Note: I wrote this post before I saw the Ringer piece, and then added that sentence and the link.) I mean just look at this:

That’s every team’s season since 1920, with our AL West friends highlighted. Now, one-run records lead to exceeeding your “expected” wins. Because those formulas use total runs scored and runs allowed, so winning close games, and losing non-close games, will make a team overpeform their expected wins. Take a look at the adjusted Baseball Prospectus standings.

The Mariners are exceeding their expected win percentage by .101! That’s 16 extra wins over a full season. (I’m using pythagenpat, or the BB reference first order expected win perentage). That would shatter the 162 game record that the 2016 Rangers hold (.081, or 13.2 “extra” wins). (The 1981 Reds playing in a strike-shortened 108 game season hold the record for “luck” of .086 above expected win percentage. Then they missed the playoffs anyway, because the division winners went to top teams in the first-half and second-half). So maybe they weren’t so lucky.)

That’s not all! If you looked at those Baseball Prospectus adjusted standings you would see the Astros are at the bottom. So, the Mariners are exceeding their expected wins by 6.8 games while the Astros are 5.1 games below their expected wins. This combines for a difference of 12 games in the standings!

The Astros bad “luck” of -0.075 if it lasted until the end of the season would be the third worst of all time going back to 1920 - behind two bad teams such that no one was that concerned about their run differential: the 1993 Mets (59 wins, expected 73), and the 1986 Pirates (64 wins, expected 77). Look at the plot from above with the Astros added: (Apologies the shade of red changed.)

Thankfully, even with this undperformance relative to runs scored/allowed the Astros are still on pace to win 102 games, based only on their current actual win percentage. I suspect/hope over the course of a long season, these numbers even out. Here in June though, yikes. Some of the data behind these plots below.

Standings and Expected Win Percentage as of games through June 12

Liveball Teams (1920 and later) With Absolute Value of “Luck” greater than .06