Adjusting 2018 Records for Strength of Schedule

With the 2018 season in the books, err… well, at least the standard 162 games in the books, I was curious to examine each team’s record in light of their strength of schedule. Now, this can be a tricky and even controversial exercise. There are different ways to determine each team’s talent level.

For simplicity’s sake, I decided to just use each team’s 2018 record as an indicator of their talent level. You could also use each team’s run differential or ELO rating from fivethirtyeight, but this was my analysis and I chose to use 2018 win-loss record.

Below you will find each team’s win total at the end of the regular season, the average winning percentage of the opponents they faced throughout the season, and their adjusted wins. The playoff teams are in bold and happen to be the top ten teams with the most wins (not a huge surprise).

Team

Wins

Opp. Win %

Adj Wins

BOS 108 0.484 105
HOU 103 0.498 103
NYY 100 0.487 97
OAK 97 0.498 97
CHC 95 0.494 94
MIL 95 0.496 94
CLE 91 0.469 85
COL 91 0.500 91
LAD 91 0.498 91
ATL 90 0.494 89
TBR 90 0.496 89
SEA 89 0.507 90
STL 88 0.498 88
ARI 82 0.506 83
PIT 82 0.503 82
WSN 82 0.494 81
LAA 80 0.513 82
PHI 80 0.497 79
MIN 78 0.480 75
NYM 77 0.502 77
SFG 73 0.513 75
TOR 73 0.509 74
CIN 67 0.516 69
TEX 67 0.520 70
SDP 66 0.515 68
DET 64 0.488 62
MIA 63 0.512 65
CHW 62 0.491 61
KCR 58 0.493 57
BAL 47 0.528 50

I used the following formula to calculate adjusted wins:

Adj Wins = Wins x Opp Win Pct x 2

I multiplied by 2 so that if a team’s opponents had a .500 winning percentage (neither good nor bad), that team’s adjusted wins would be the same as their actual wins.

To help make this method more clear, let’s examine two teams with the same number of actual wins. The Colorado Rockies and Cleveland Indians both won 91 games. However, the Rockies opponents had an average winning percentage of .500, while the Indians opponents had an average winning percentage of 0.469 (due to the fact that AL Central teams were just awful this year).

Given their strengths of schedule, 91 wins sounds a bit more impressive for the Rockies than it does for the Indians. So while the Rockies adjusted win total matches their actual win total of 91, the Indians adjusted win total is only 85.

In fact, the Indians are the team whose win total went down the most after adjusting for strength of schedule. They had the easiest schedule according to this measure, which isn’t surprising given that everyone else in their division finished at least 6 games below .500.

If we sort the table based on Adjusted Win total, we get the results below. WARNING TO SEATTLE AND TAMPA BAY FANS: The table below might stir up feelings of bitterness and resentment.

Team

Adj Wins

Opp. Win %

Wins

BOS 105 0.484 108
HOU 103 0.498 103
NYY 97 0.487 100
OAK 97 0.498 97
MIL 94 0.496 95
CHC 94 0.494 95
COL 91 0.500 91
LAD 91 0.498 91
SEA 90 0.507 89
TBR 89 0.496 90
ATL 89 0.494 90
STL 88 0.498 88
CLE 85 0.469 91
ARI 83 0.506 82
PIT 82 0.503 82
LAA 82 0.513 80
WSN 81 0.494 82
PHI 79 0.497 80
NYM 77 0.502 77
MIN 75 0.480 78
SFG 75 0.513 73
TOR 74 0.509 73
TEX 70 0.520 67
CIN 69 0.516 67
SDP 68 0.515 66
MIA 65 0.512 63
DET 62 0.488 64
CHW 61 0.491 62
KCR 57 0.493 58
BAL 50 0.528 47

The playoff teams are in bold again, but they aren’t the top 10 this time, with both the Braves and Indians coming in behind some teams that didn’t make the playoffs.

Also note that while the Red Sox adjusted win total is 3 less than their actual wins, they still maintained the top spot. The Yankees also lost 3 wins after adjusting for strength of schedule, but remained in the #3 spot. In fact, the top 4 spots remain unchanged.

The Rangers and Orioles were the teams with the hardest strength of schedules according to this measure. This makes sense since they were the worst teams in the two divisions that featured the top 4 teams.

As far as the Astros, they had a pretty average strength of schedule according to this measure. I’m a bit surprised to be honest, because the AL West was a pretty good division this year; if the Angels had won just one more game, than the Rangers would have been the only sub-.500 team in the division. The Astros did get to play 7 games against both the Orioles and the White Sox though.

Like I said, this is only one way to measure strength of schedule and perhaps not even the best one. I think it does a good job, though, since it doesn’t really mess with the standings too much. The Indians are actually the only team with a difference of more than 3 between their actual wins and adjusted wins.

What do you think? Are you surprised by these results?