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A word about strike outs...

KISSIMMEE FL - JANUARY 28:  Practicing umpire arguments at an academy of professional umpiring. (Photo by Al Bello/Getty Images)
KISSIMMEE FL - JANUARY 28: Practicing umpire arguments at an academy of professional umpiring. (Photo by Al Bello/Getty Images)
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I think baseball fans overrate the impact of hitters' strike outs. I made a comment in another thread to that effect, and it's worth elaborating on why. Obviously strike outs are not a good outcome in any particular at bat. But keep in mind that Reggie Jackson led the AL in strike outs five time and is the major league leader in career strike outs. Although a completely different era, Babe Ruth also led the AL in strike outs five times. My point is this: if you are evaluating the hitting careers of Reggie Jackson and Babe Ruth, strike outs are not a very illuminating statistic.

To demonstrate my point, I used fangraphs' data to compare ML team offensive statistics for the period Mar/April 2010 to current. I tested the strength of the relationship between team strike out percentage and other team offensive statistics using R-squared. R-squared is a measure of the correlation between variables.

Team strike out percentage is not correlated with runs scored, wOBA, ISO, BABIP, OBP, Slugging and wRC+. The R-squared is less than .03 for wOBA, ISO, and BABIP, and less than .10 for OBP, Slugging, and wRC+. The R-squared is .11 for Walk Rate, indicating that higher strike out rates are correlated to a minor extent with high walk rates. The only R-squared which is meaningful is batting average (.33). Team strike out rate is moderately related to team batting average, in that more strike outs tend to reduce the batting average. This isn't surprising, since strike outs are a measure of one type of out. But, with the exception of batting average, strike outs are not a significant determinant of team offensive production.

Since the beginning of last season, the Astros' strike out rate is lower than the strike out rates for the World Series champion Giants and offensive powerhouses like the Yankees, Red Sox, Tigers, and Reds. Although the Astros have the 9th lowest strike out rate over that period, the Astros produced the fourth lowest run total.

So what statistics are related to scoring runs?

For the same period, the following team offensive statistics are strongly related to runs scored.

Relationship to Runs Scored (R-squared)

wOBA 0.92

wRC+ 0.86

OBP 0.82

SLG 0.81

Batting Avg. 0.48

Fangraphs' wOBA statistic (basically a more accurately weighted form of OPS) is closely related to scoring runs. Although batting average is correlated with scoring runs, batting average is much less important than wOBA, wRC+, OBP, and SLG as a determinant of runs scored by a team. This is one of the reasons that batting average is an inferior measure of offensive performance. Strike out rate has a moderate effect on team batting average, but has no real effect on the offensive statistics which are most closely related to scoring runs. The relationship between strike out rate and runs scored has a R-squared of .015, which is obviously insignificant compared to the R-squared for OBP, SLG, wRC+, and wOBA above.

Strike out rate tells you little about the ability to produce runs. Look to statistics like wOBA and Runs Created to tell you something meaningful about run production.