Tuesday, May 31, 2016

Which teams' actual ERAs were the farthest below their FIP ERAs since 1900?

Data used here comes from Fangraphs and Baseball Reference. In the table below, DER is defensive efficiency rating. That is the percentage of balls in play converted into outs. Rank is where the team ranked in DER in their league for that year. Lg Avg is the league average DER for that year.


Team Year ERA FIP Diff DER Rank Lg Avg
Yankees 1939 3.31 4.26 -0.95 0.694 1 0.685
Giants 1933 2.71 3.49 -0.78 0.719 1 0.702
Giants 1934 3.19 3.95 -0.76 0.704 1 0.685
Reds 1999 3.99 4.74 -0.75 0.722 1 0.687
Giants 1954 3.09 3.83 -0.74 0.722 1 0.707
Athletics 1929 3.44 4.16 -0.72 0.703 1 0.687
Giants 1936 3.46 4.18 -0.72 0.693 2 0.684
Indians 1948 3.22 3.94 -0.72 0.731 1 0.704
Braves 2002 3.13 3.83 -0.70 0.712 2 0.695
Twins 1965 3.14 3.84 -0.70 0.724 3 0.715
Robins 1930 4.03 4.72 -0.69 0.693 1 0.669
Cubs 1906 1.75 2.43 -0.68 0.736 1 0.698
Cubs 1935 3.26 3.93 -0.67 0.696 2 0.686
Reds 1939 3.27 3.94 -0.67 0.708 1 0.695
Yankees 1955 3.23 3.89 -0.66 0.733 1 0.710
Orioles 1973 3.08 3.74 -0.66 0.731 1 0.701
Yankees 1935 3.60 4.26 -0.66 0.713 1 0.687
Bees 1937 3.22 3.88 -0.66 0.714 1 0.689
Athletics 1990 3.18 3.84 -0.66 0.732 1 0.699
Braves 1956 3.10 3.75 -0.65 0.726 2 0.716
White Sox 1967 2.45 3.10 -0.65 0.735 1 0.718
Reds 1940 3.05 3.69 -0.64 0.730 1 0.701
Giants 1931 3.30 3.93 -0.63 0.706 1 0.687
Yankees 1957 3.00 3.62 -0.62 0.727 1 0.713
Tigers 1982 3.81 4.43 -0.62 0.725 1 0.704

Twenty of the top 25 teams ranked first in DER. That makes sense, since if you turn alot of balls in play into outs, you will give up fewer runs (and fewer than expected based on walks, strikeouts and HRs, which figure into FIP ERA). The 1939 Yankees had a 106-45 record and the all-time best run differential of 411.

Teams might also see their actual ERA go below their FIP ERA if they pitch well with runners on base. But my post last week showed that although that matters, DER probably matters more.

Twelve of these 25 teams came between 1929 & 1940 (I wonder what the reason is). Many of the 25 were pennant winners or made the playoffs.

Four Giants teams from the 1930s are on the list. They led the NL in DER 4 times in the decade and were 2nd three times. They also led in fielding pct. 4 times with one 2nd. They had the highest DER for the decade of 0.7001 (2nd place had 0.6960). Maybe they are one of the great fielding teams in baseball history. But it is not anything I have ever heard about.

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