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”.

What is Zone Rating in Sport Betting?

The main sport channels, ESPN, shows the Zone Rating as percentage, which was evaluated by STATS Inc., of balls on the player’s field in his typical defensive zone. STATS Inc. is one of the leading providers of the statistical information in the spheres of professional sport and sport competitions, which has been tracing the position of every particular ball in every game since 1990.

To define the ZR, the field is mentally decided into 20 different zones. Every player in turn is responsible for every ball in his zone. And he doesn’t responsible for any balls outside his zone. In fact, it is the definition for ZR as a parameter. To concrete, it is a field, which has the shape of a heart (as the hearts in a deck of cards) and is cut into many thin pieces. The bottom of the heart is home plate. And every player on the field is responsible for all the fitlding balls, which were thrown in his zone.

The main prerequisite of a zone is that a fielder is considered to be responsible only for the moment, in which he really can struggle (i.e. write “out” into his account). ZR just counts the total number of the outs, which were registered by a fielder and the total number of possibilities (hits) in his zone. Just in case if you want to know the average ZR for all the teams it’s about 85 percent. At the average the MLB players will make outs in 85% of 100 hits in their “zone”.

Zone Rating Can Be Very Useful When Bet on Football or Baseball

You should know some things about ZR. At the beginning of a game not all the balls are counted. The balls that were thrown lower than the line, higher than the middle or in nobody’s (i.e. not assigned) zone, for example, are ignored. If ZR has a problem, it is only that the zones are very thin and the players with “good hands” receive an advantage over the players with “good radius of action”. But STATS obviously made the smaller zones purposefully in order to reduce the possibility of the players, so they can’t “encroach” into the zone of their neighbours.

Even in this case, ZR gives a head start to fielding percentage in amount of 100 points, as a criterion for evaluating the defensive ability. Unlike fielding percentage, there are no subjective elements in ZR, as ZR clearly defines the obligations (of zone), every fielder of which is supposed to be responsible. When we choose fielding percentage, we allow the referees to be responsible for the mistakes, as their opinions may be different from each other (that is why at least one of them will be mistaken) when they interpret the same game situation.