Defensive Efficiency Record (DER) is an answer to this question:  When a ball is put into play against this team, how often does the defense turn it into an out?   I developed the DER back in the 1970s, the same era when I developed Runs Created and the Pythagorean Method and the Defensive Spectrum and stuff, but it did not reach an audience in the 1980s, did not come into common usage, because I had made the original formula so complicated that it was hard to use.  It was what I used to call a 40-pound garden hoe. 

            DER basically died off, but somebody came along later—I do not know who—and cleaned up the formula, which brought it back to life.  In  measuring DER I had tried to include Errors as plays not made—thus, indications of Defensive Inefficiency.   But since not all errors put runners on base, I then had to estimate how  many of the errors were not relevant, which complicated the process.  Also, my original formula tried to make two different estimates of Balls in Play, one derived from the pitching stats and one derived from the fielding stats, and then put them together, average them out.   The resulting formula was so complicated it was unusable. 

            The formula we use now is just this:

            BFP – BB – SO – HBP – HR  =  BIP (Balls in Play)

            DER= (BIP – (H – HR))/ BIP

            Over time, DER varies, but does not vary a lot.   In the last 120 years the normal DER has been as high as .729 in the 1950s and 1960s, and as low as .705, in the last decade (2010-2019).   The highest DER ever for a team was .763, by the 1906 Cubs (Tinker to Evers to Chance), and the lowest ever was .660, by the 1930 Phillies.  "Ever" meaning since 1900.    And, since I have come this far in that direction, these are the DER norms for each decade of our study:

            And, since it is our habit to do this, these are the standard deviations:

            There is a remarkable change in the standard deviation of team defense in 1920.  1920, of course, is the great line of demarcation in baseball history—the simultaneous emergence of Babe Ruth, the banning of the spit ball, the Black Sox Scandal, the Commissioner System, and the death of Ray Chapman.   The vortex created by the convergence of these events changed baseball dramatically overnight.  We see here another manifestation of that:  a standardization of defenses, with the standard deviation of DER dropping suddenly, probably due to the disappearance of common bunting. 

            DER is lower now because we are in the throw hard, swing hard era.  More contact is hard contact.   There are more strikeouts, but fewer balls in play result in outs. 

            We are interested, of course, not in DER directly, but in era-normalized DER, normalized by Standard Deviation.   Once we lead our numbers through their dance, the highest DER of all time belongs not to the 1906 Cubs, but to the 2016 Cubs—a World Championship team, as I recall. 

            All ten of those teams had winning records, and four of them won 103 games or more.   In fact, in running down the list of teams with the highest DER ever, era-adjusted, you don’t find a team with a losing record until you get to the 50^th spot.   The 1971 California Angels had a losing record (76-86) despite having a Defensive Efficiency Record that was two standard deviations above the norm for the era (120).  If you look at the roster, you can understand it; their lineup was littered with light-hitting defensive wonders like Jim Spencer, Ken Berry and Sandy Alomar Sr., but their 3-4 hitters were guys who should have been hitting 7^th and 8^th.  For the season, their leadoff hitters had an on base percentage of .295, and their #2 hitters and on base percentage of .285, while their third hitters had a slugging percentage for the season—SLUGGING percentage—of .319, and their cleanup hitters had a slugging percentage of .352.

            So that team had a historically outstanding defense but a historically awful offense, but the 49 teams who had higher normalized DER all had .500 or better records.    DER is more closely connected to winning than anything else we have studied:

            I think the conclusion that the 2016 Cubs had a historically great team defense stands up to scrutiny.   Their first baseman, Anthony Rizzo, was named the major league’s best defender at any position—a conclusion that he himself mocked, saying that a first baseman should never win that award—but anyway Rizzo was an outstanding first baseman.  They had not one outstanding defensive shortstop on the team, but two, with Addison Russell and Javy Baez; Kris Bryant was really good at third base, and two outfielders were defensively outstanding, Jayson Heyward and Dexter Fowler.  Ben Zobrist moved here and there and held the defense together whenever and wherever there was an injury.   Their catchers had some defensive issues, but catchers don’t feed very much into DER; what catchers do is important, but it’s not DER.   They had some defensive issues in left field, but then, who doesn’t?

            I have made this point before about the 1906 Cubs—that that team, over a period of years, won more games than any other team ever; they went 116-36 that season, but over a period of ten years and more, they had better won-lost records than any other team, ever.  Tinker, Evers and Chance have to be given a lot of credit for that.   If you judge their pitchers by wins, losses and ERA, you will think that they had fantastic pitching—but if you look again, you’ll realize that (a) their pitcher’s strikeout and walk data is actually not all that good, (b) home runs are a minor element of the game at that time, and (c) almost none of those great pitchers was anything special when he wasn’t pitching for the Cubs.   Three Finger Brown was no doubt legit, but they picked up a lot of guys who were just very ordinary pitchers with other teams, and they suddenly became brilliant pitchers as soon as they put on a Cubs’ uniform.  The defense behind them made their pitchers look a lot better than they really were. 

            Look at the 2016 Cubs, you see something similar.  Jake Arrieta was 22-6, 1.77 ERA in 2015 and 18-8, 3.10 ERA in 2016.  The rest of his career, he’s just not that good.  Kyle Hendricks in 2016 was 16-8, 2.13 ERA.   He’s just not really that good.  The 2016 Cubs’ defense was making pitchers look better than they really were.   They haven’t been able to hold it together in the three years since then, keep it at that level, but I believe that that really was a historic defensive team. 

            DER confuses cause and effect, to a certain extent—cause, effect, and luck.  In other words, it may not be that when you have a great DER you win; it might be, rather, that when you win you have a great DER.  When things break your way, when you have a season when your own line drives go through and the other team’s line drives find somebody’s glove, then you have a high DER, and you win, and you look better in the statistics than you really are.   What I am saying is, you CAN over-value defensive efficiency, but you cannot deny that it is very closely tied to winning.   It’s a chicken-and-egg question; does a high DER cause winning, or does winning cause a high DER?   Some of each, probably.

            The 1930 Philadelphia Phillies had not only the lowest DER of all time, raw, but also the lowest compared to their era.  These are the bottom 10:

            The 1930 Phillies are a famously awful team that managed to lose 102 games despite having one outfielder who hit .386 with 40 homers, 170 RBI and another one who hit .383 with 22 homers, 97 RBI.  Obviously it was an atypical league, an atypical park, a kind of crazy combination of circumstances, and both the pitching and the defense were so bad that it is hard to say for sure which was worse. 

            All of those teams with the lowest DER lost 90 or more games except the 1987 Red Sox and the 1914 Baltimore Terrapins.  The 1987 Red Sox had a decent offense and the best pitcher in baseball, Roger Clemens, so they were able to go 78-84 despite their god-awful defense.  78-84 still is not good, but they avoided 90 losses.  The 1914 Terrapins finished 84-70, but that was in the Federal League, an upstart league; the statistical parameters are just a little bit misaligned with the era.   Basically, a low DER means that you lose. 

            The highest DER of all time, normalized for the era, was 3.7 standard deviations above the norm; the lowest was 3.9 standard deviations below the norm. 

            It has always been my belief that the #1 key to a high DER is speed in the outfield.  I can’t really PROVE that; it’s an informal observation, and sometimes it’s hit-and-miss.   I’m not saying that having range in the infield isn’t important; it is.   The 2001 Seattle Mariners had Mike Cameron in center field and Ichiro in right.   They had the second-highest DER ever, era-adjusted, and won 116 games.  The 1939 Yankees had DiMaggio in center field and four other outfielders who could have played center field if they had needed to.  There is no single key to winning, and having speed in the outfield is not the key to winning; you won’t win with fast outfielders unless they put some runs on the scoreboard as well.  But I still believe that having speed in the outfield is the #1 key to a high DER, and a high DER is one of the keys to a successful team. 

            That’s why I am relatively optimistic about the 2020 Red Sox, if we are ever able to get the season started.  With an outfield including Kevin Pillar, JBJ, Benitendi and Alex Verdugo, they’re going to catch everything that can be caught, and this will largely offset the effects of having maybe not the quickest shortstop in the league, or the second-quickest, or the third-quickest.   But we’ll see.