Saturday, October 25, 2014

2014 Record



At its heart, what sabermetrics asks is how to maximize wins. The answer, as simple as it is, is to score more runs than the other team. That’s a statement John Madden would be proud of. Of course, it’s difficult to assess how good a team is at scoring more runs than their opponents, but the first and easiest place to start is run differential.

Run differential (runs scored minus runs allowed) is the first place to go to understand exactly how well a team performed. Teams with good records but low run differentials tended to be “lucky” while teams with bad records but good run differential are a good team hit by bad luck. Bill James researched this and came up with a way to predict a team’s record given its run differential. He dubbed it the Pythagorean Expectation due to its similarity to the Pythagorean Theorem: Wins = runs scored ^ 1.83 / (runs scored ^ 1.83 + runs allowed ^ 1.83). Given a team’s runs scored and runs allowed, this formula predicts win-loss record with surprising accuracy. Of course, baseball is a game of funny bounces and sometimes the actual win-loss record doesn't come close to the expected win-loss record based on run differential. What to make of that? Teams regress to the mean and don’t have the ability to consistently beat out their run differential year over year. You end up with a few outliers each season, but most teams clustered around their expected record, a bell shape curve if you will. Those outlier teams? Next year they are likely to end up right back in the middle where you would expect.

So how does the Nationals’ run differential look and what can that tell us about the 2015 team? Well, The Nationals finished 2014 with a 96-66 record, good for the best record in the National League, outscoring their opponents by 131 runs. That run differential was good for 3rd best in MLB behind only the Angels and the A’s. Based on Bill James’ formula the Nats… won exactly how many games you would expect them to. We all knew the 2014 team had a lot of talent and that talent played out pretty much how you would expect during the regular season. There is nothing in the run differential that screams regression to the mean or problems for next season. Compare that, for example, to this year’s Oakland A’s. They had the 2nd best run differential in the majors that results in an expected win-loss record 11 games better than they actually performed (from an actual record of 88-74 to an expected record of 99-63).  The A’s were a really good team that slumped badly at the end of the year.

Fangraphs tracks what they call “BaseRuns” which takes the total offensive output of a team (singles, doubles, homeruns, etc), weights each event for its overall value in scoring runs, and spits out an expected win-loss record. It’s not substantially different from the Pythagorean analysis, but it’s another data point. Again, the Nats are pretty much right where you would expect, with Fangraphs giving them an expected record of 97-66, one win better than actual.

The last place to look when it comes to a team’s performance is their record in one run games. These are the games that may literally come down to one bounce of a ball, an event outside of the control of anyone on the field. As such, it has been shown that teams, regardless of ability, tend to win as many one run games as they lose. Just like with run differential, records in one loss games tend to regress to the mean. As I’m sure you are expecting by now, the Nationals were 26-22 in one run games in 2014. Over .500, sure, but not by a substantial margin. 

Ok, so 600 words later, where does that leave us? The Nationals were a really good regular season team. Of course, we all knew that. What to explain the quick exit from the playoffs? Does it have something to do with the makeup of the team? Perhaps they are good in the regular season because they get to play the Phillies and Mets of the world on a consistent basis but can’t hack it against quality competition? Well, versus teams that made the playoffs, the Nats went 17-20 in the regular season. Against everyone else? A whopping 79-46. Aha! There must be something about the team that they don’t perform well against the elite teams.

Not so fast. Take a look at the breakout for every playoff team:

Vs. Playoff Teams
Vs. Non-Playoff Teams
Overall

W
L
W
L
W
L
STL
24
23
66
49
90
72
LAD
24
26
70
42
94
68
PIT
23
24
65
50
88
74
SFG
20
29
68
45
88
74
BAL
18
18
78
48
96
66
DET
32
18
58
54
90
72
LAA
22
23
76
41
98
64
KCR
25
24
64
49
89
73
OAK
23
23
65
51
88
74

Only one team performed more than 1 game over .500 against playoff competition, and the Tigers got busy setting up their tee times much earlier than they expected. The moral of the story? As Billy Beane puts it, “my shit doesn’t work in the playoffs.” The playoffs, especially for baseball, result in unpredictable outcomes.

No comments:

Post a Comment