In this post I would like to talk about defensive efficiency rating. How this rating can make influence on you sports betting strategy in particular in baseball or football betting. Most of my friends that bet regularly don’t pay attention to this value. I think it’s wrong way. Here I will describe why.
Earlier posts about this topic:
Team Defense in Football and Baseball Betting #1
Role of Team Defense in Baseball and Football Betting #2
Baseball and Football Betting: Team Defense #3
Defense in Football & Baseball Betting #4
How Important DER in Sports Betting
Defensive Efficiency Rating is a simple measuring system. It is based on the number of the stricken balls (except home rounds), which then are turned into outs. The main prerequisite for DER is that the defenders of the team have to catch every ball, which was batted on the field, except home rounds. The average DER for all the teams constitutes about 70%. In other words, 7 of 10 batted balls (except homers) will be turned into outs.
DER may look like quite a rough evaluation of the defensive ability, as the defense depends on the pitchers very much. A good pitcher, of course, can improve the defensive rating, and at the same time a bad pitcher can reduce it. And DER does not take into account the influence of the game park. Some parks are better for the defense than others.
In spite of its imperfection, DER refreshes, because (like ZR) it allow us to avoid the subjective nature of fielding percentage. And finally, counting the fielders’ responsibility for the balls, which were batted in their zones, it doesn’t seem very severe, because this is the reality of the game.
Summing up the discussed information, I would like to notice that the betting statisticians are used paying attention to the defense less than pitchers and batters. The good news: statistical minds and other gurus have recognized the problem and work on the improving of characteristics, which allow to evaluate the quality of playing on a field.
From the position of betting, we can’t say how important the evaluation of defense is, when you forecast the final result of a competition.
It might be less important than hitting and pitching, but you can’t fully ignore the defense during the baseball handicapping. Though Zone Rating and Defensive Efficiency Rating are not perfect, but they are very reliable. At least they are much better than just fully ignoring of defense or using the useless indices like “Fielding percentage”.