All Choices Involve Tradeoffs

From economist Cy Morong.

The correlation between the change in strikeout rate and the change in contact rate was .142. So if a batter’s strikeout rate increased, his batting average while making contact also increased. Looking at the changes from 2005 to 2006 gave a .18 correlation.

Maybe this makes sense. If you swing harder, you strike out more. But a harder swing means the ball is hit harder, which should mean more hits. So combined with the earlier study, a player should be careful if he thinks he should make a big effort to strikeout less.

4 Responses “All Choices Involve Tradeoffs”

  1. ChuckO says:

    I don’t know what this really proves. It could be the case, as Morong suggests, that a harder swing means the ball is hit harder, which should mean more hits. However, it could also be the case that the batter whose strike out rate increases has learned to be more selective. Hence, he’s taking more pitches in the strike zone while looking for something that he can hit. This increased selectivity would presumably lead to more hits, but also to more called strikes and, hence, strikeouts.

    I don’t know what the real reason for the correlation, but I don’t buy Morong’s explanation. He’s making too many unjustified assumptions. He’s assuming that when a batter strikes out more, it’s because he is swinging harder. He’s also assuming that a harder swing means that the ball is hit harder. That’s not necessarily the case. A harder swing could lead to less solid contact. Finally, he assumes that when a ball is hit harder it’s more likely to be a hit. That might seem intuitively true, but is there any evidence for it?

    In short, it’s an interesting correlation, but it requires an evidence-based explanation.

  2. Marc Schneider says:

    That assumes that a harder swing means the ball is hit harder.  Do we have any physical evidence that that’s true?  I can imagine a scenario where trying to swing harder somehow reduces bat speed or some such.  And, even hitting the ball harder might not produce more hits; if you hit a long fly ball that goes over the fence, that might not be hit as hard as a line drive single.

    I can accept the idea that there is a tradeoff between strikeouts and power so that reducing strikeouts isn’t always good.  But, there is a threshold; there is some point at which the lack of contact outweighs the additional power–I think this was true for Ryan Howard for much of the season.

    There is also a situational factor.  There are clearly some situations where a strikeout is worse than another kind of out; the Yankees won the 1962 World Series on a double play grounder with the bases loaded–if the batter had struck out, the run would not have scored.

  3. Vince says:

    Could this just be a selection effect?  If your strikeout rate rises and your contact rate falls, then you might get benched and not show up in the sample.

  4. Cyril Morong says:

    There were 267 players in 2005 who had 300+ ABs. 200 of them also had 300+ ABs in 2006. So it is possible that those 67 who did not make it to 300 in 2006 were benched for poor performance (which would include a low contact average).

    But I took those 67 guys and found the ones who had atleast 100 ABs in 2006 (I think anything less is a small sample size). That left 41 guys. The correlation between their change in strikeout frequency and change in contact average was .037.  So it was still positive for the ones who were “selected out” but not as strong an effect.