Tango (at The Book blog) takes this question on with a rather ingenious analysis. The "with and without" approach to analysis is widely used in many disciplines. The idea is to ask, how many runs did the Astros allow when Adam Everett is in the lineup and when he isn't? But over the course of a season so many factors are at work, that we can't attribute all the differential in saved runs to Everett, alone.
Tango addresses this issue by examining enough great fielders over a long period that the sample size overcomes the other factors. An excerpt:
So, using WOWY (With Or Without You) based on balls in play, I selected the best twenty or so infielders (2B, SS, 3B) since 1993. It’s mostly the names you know: Everett, Sanchez, Bartlett, Rolen, Reese, Hudson, Inge, etc. By looking at a large enough number of great infielders, the idea is that all the noise around them will cancel out. My only additional constraint was that he must have been on the field for at least 1000 outs for a given team-season, and must have been off the field for at least 1000 outs for that same team-season.
I came up with 68 such seasons since 1993. The total number of games played was 5386 games on the field and 5400 games off the field. You have to admit that that’s alot of games. When the star fielders were on the field, their team allowed 4.60 runs per game, and when they weren’t on the field, they allowed 4.83 runs per game. Per 162 games, this difference comes out to 37 runs.
So his conclusion is that a great infielder like Adam Everett will be worth 37 runs, on average, defensively, per year.
He then performs the same analysis for outfielders and first basemen. The averages come out to 19 runs and 15 runs, for great outfielders and great first basemen, respectively.
Tango obtains a weighted average for the positions on the field, and concludes that a truly great defensive player on a team is worth on average 25 runs in a season.
0 recs | 3 comments
okay, and maybe this wouldn't skew the numbers much,
but couldn’t there be a tendency amongst teams with a great defensive player to value defense more highly than other teams? So maybe the backups on these teams were better defensively (on average) than other teams’ players.
Alternatively, these teams might decide to go for more offensive firepower off the bench, and so select for better offensive players but poorer defensive players. Could swing either way.
Only_A_Lad - March 6, 2009
true, but it would have to be systematic across all teams to make much difference.
I suspect teams are divided on how they handle the back ups. Most teams want a mix of offensive and defensive players on their bench. Whether an offensive or defensive bench player backs up the “great defender” may be happenstance. It may be tilted one way or the other way by the position of the great defender. I am guessing it doesn’t affect it much.
Thinking about Everett, his back ups have been Blum, Vizcaino, and Bruntlett. Bruntlett is the only “mostly defense” player among the three. Blum was more offensive oriented. Viz was kind of balanced, though not great as either a defender offensive player.
I think this approach can be used as confirmation (in a general way) of the “runs saved” calculated by play-by-play metrics like UZR. Some fans have a strong skepticism of defensive metrics. For example, at his peak, defensive metrics were showing Adam Everett as a 29 -39 runs saved player, depending on the system. I know some people (here and elsewhere) would refuse to believe that is possible. Tango’s calculations show that it is possible.
clack - March 6, 2009
yeah
and I wouldn’t say that Everett’s backups were ever “defensively oriented.” And, even if the vast majority of teams with a “great” defender have a different way of choosing backups, it depends upon how much different those replacements are from the average bench player. That might come out to only a few runs a year, though, so it probably doesn’t matter much.
Only_A_Lad - March 6, 2009
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