What is Defensive Efficiency Ratio (DER)?

Defensive Efficiency Ratio is the percentage of ball in play that a defense convert into outs/

The formula for Defensive Efficiency Ratio is: 1 – ((H + ROE – HR) / (PA – BB – SO – HBP – HR)).

This stat  is used because looking at a team’s defense just by their fielding percentage is misleading.

Due to things like the popular defensive shift is becomes hard to know jut how good or bad a team’s defense really is. Even with the use of other defensive metric like DRS and UZR some time a really good or bad defender gets lost in the numbers for the team.

Fielding percentage doesn’t take into affect things like a player range on the diamond but DER is useful to a greater detail comparing players to other teams or season or even past decades.

This stat is mostly helpful if you are a DFS player as it allows you a peak into which pitcher to place into your active lineup.

Defensive Efficiency Ratio Comparable chart

Excellent     .720 or above

Good             .710

Average         .700

Below Average .690

Terrible            .680 or below

When post season awards or to be given out. The Cy Young Award and DER should help between players as was the case in 2014 in the AMerican League between Corey Kluber and Felix Hernandez. Their numbers were similar. The Mariners squad and Hernandez had a league best DER and the Indians and Kluber were not a s good. This is not the definative numbers to select a Cy Young winner but should be in the mix when having the discussion. DER can influence the ERA of a pitcher.