When a batter swings at the first pitch does that reduce or enhance his odds of getting a hit? This week on SABR-L David Smith of Retrosheet posted some hard numbers to try and answer this question that originated from a college baseball coach. The data were further analyzed by Bruce Cowgill and break down as follows:
BA OA SA OPS
Swing 0.282 0.302 0.457 0.759
NoSwing 0.259 0.346 0.413 0.759
Total 0.266 0.334 0.426 0.760
This includes data from 2003 and 2004 up to September 14th comprising 345,905 plate appearances. It's interesting that the OPS numbers are almost identical between the two groups but as you might expect the OA goes up when a batter doesn't swing on the first pitch although the batting and slugging averages go up. In addition, hitters swing at the first pitch 27% of the time and take it 73% of the time.
In another post Cyril Morong found that for this season OPS correlated with run scoring to the tune of .973. Squaring this value gives .947 which means that 94.7% of the variation in team runs was explained by OPS. This is another indicator of why OPS is so valuable as a quick means of assessing a player's offensive value. Morong also reported that the authors of Curve Ball found a correlation of "just" .914 making the r-squared .835. Reasons that OPS may correlate better this year than in the past include luck, increased homeruns and therefore decreased stolen bases and one-run strategies, or an increase in strikeouts. Time will tell whether higher correlations between run scoring and OPS is a trend or not.