Originally Posted by vaticanplum
Two questions, Cyclone:
1. How is DER determined?
2. Would you mind giving up your life for a while so you can do this for every team in the Central? Thanks.
It looks like the definition that ochre gave you was DIPS ERA, which is different from DER (Defensive Efficiency Ratio). But ochre did provide some very good information regardless so that's always a good thing!
Anyhow, defensive efficiency ratio is a team defensive stat used to measure the effectiveness of an overall team's defense to turn batted balls into outs. The only definition I've been able to find is located on the Hardball Times Glossary
page. That definition reads as follows ...
Defense Efficiency Ratio. The percent of times a batted ball is turned into an out by the teamsí fielders, not including home runs. The exact formula we use is (BFP-H-K-BB-HBP-Errors)/(BFP-HR-K-BB-HBP). This is similar to BABIP, but from the defensive team's perspective. Please note that errors include only errors on batted balls.
Now in the DER figures I've posted in my charts above, I've made a slight adjustment in the formula itself, and that is I eliminated errors from the formula. The reason is because the errors included in the formula are only errors on batted balls, and unfortunately I'm unable to see every game. What happens is it becomes very difficult to differentiate errors based on only a boxscore description if I didn't see the play myself. To account for that, I just made it simple and cut the errors out of the formula altogether. Since errors comprise of a very small percentage of a team's overall fielding chances, and since most teams have a similar number of errors each season, it hasn't been much of an issue.
Now MLB.com has a page
where you're able to view all 30 MLB teams' DER and sort by best/worst. I have no idea what exact formula they use, but after 13 games their DER figures match mine. It's possible they may have just eliminated errors too. An added benefit is each team's errors and fielding percentage is also included in that same stat set.
Now as to your second question, I'll have to politely decline.
But you're in some luck since it seems that Baseball Reference is finally updating most of their content on a daily basis. For example, now you can go to the 2007 National League
index page and easily be able to see some basic stats for all NL teams, such as runs scored/allowed per game, team ERA, team BA/OBP/SLG, etc.