Saturday, October 24, 2015

Daniel Murphy and the nature of hot streaks

That is Strat-O-Matic's depiction of Daniel Murphy's 2015 postseason so far. I'm gonna guess that even those unfamiliar with Strat can figure out what's going on there.

But it's just 38 at-bats and 39 plate appearances, the very definition of small sample size. Murphy has more than 3,600 plate appearances in his career that paint a different picture of his abilities.

The results of a Strat game are essentially random, literal rolls of the dice. If Jose Bautista hits more crucial homers than anybody else, it's because Jose Bautista hits more homers, period. And for many of a sabermetric bent, this is not only credible but accurate. This piece, from the FiveThirtyEight data journalism site, argues that a Murphy-like streak should happen every two years or so -- and notes that even this year, Jorge Soler of the Cubs has had a hotter postseason than Murphy.

Soler's team lost to Murphy's, however, so the narrative belongs to the Murph.

Every attempt I've seen to empirically study the subject of "the hot hand" concludes, in effect, that there's no such thing. A player who homered yesterday and homered again today is not more likely to homer tomorrow; he's actually less likely to do so. I think most of us intuitively realize that; it's why we're so startled with Brian Dozier hits a pair of walk-off homers in a week's time and why every Murphy four-bagger now is greeted with a mass roar of Are you kidding me? 

That said, I doubt hot streaks are entirely random chance. I think we've all had days when things just clicked better for us, not necessarily athletically but mentally and emotionally as well, times when our internal rhythms meshed well with the rest of the world. But maybe I just want to believe that baseball and life aren't just random.

At any rate: The postseason now goes on hiatus until Wednesday for the benefit of Fox's scheduling. If ... when ... Murphy doesn't hit a home run in every game of the World Series against Kansas City, there will be chatter that the break cooled him off. An alternative interpretation would be that he was destined to return to being Daniel Murphy. It's just not realistic to expect him to slug 1.026 indefinitely.

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