November 18, 2017

Extra Rates

I was curious to see if triples were continuing to disappear from the game, but thought it would be good to look at the rates of all three types of extra-base hits over time. This spreadsheet contains a graph of extra-base hit rates per game since 1957 (the period covered by the Day by Day Database). The moving average is based on four seasons.

First, triples do continue to disappear. After making a comeback in the 1970s, triples have declined in every decade since. Triples are comparable to one-run strategies like stealing bases or bunting to move runners. Taking an extra base is worth the risk of an out when runs are scarce.

Note that doubles and home runs tend to move in tandem, although from season to season, home runs tend to spike more than doubles. During the 1980s, for example, the doubles tend is fairly flat while the home run trend shows a nice hump.

Note two that the end of the PED era* saw a shift from home runs to doubles, as the two-base hit took longer to go into decline. Maybe balls that would have cleared the fence earlier became wall scrapers.

*That is a convenient name for the era. There were trends in ballpark construction, valuing hitters over pitchers, maybe even changes in the baseball that contributed to the rise in home runs.

Right now, the double rate is not really following the big spike in the home run rate. Players are hitting more doubles, but not a lot more doubles. Home runs blew past the 2000 season peak, while doubles have not approached the 2007 peak.

1 thought on “Extra Rates

  1. Pft

    I would say triples and doubles to a lesser extent are most effected by smaller parks a rash of which came into play in the last 20 years. Parks in Arizona and Colorado play small for HR but dont hurt doubles since they are large parks. In Fenway of course HR are suppresssed and replaced by doubles or singles. The shorter porch in YS3 not to mention the short wall height suppress doubles in favor of HR, and bringing in the fences in Mets, Marlins and Mariners parks, as well as the Astros CF reduce triples and perhaps to a lesser extent doubles.

    The extra juiced ball introduced by incoming Manfred in 2015-2016, to distinguish it from the juiced ball introduced by the incoming (at that time) Bud in 1993-1994 also hurt triples as the higher EV allows fielders to get to balls off the fence quicker (especially in smaller parks). This may also suppress doubles in some smaller parks

    The only clear winner is HR which has suppressed rates seen in the so called steroid era despite historic highs in K rates brought about by Bud messing around with the strike zone to give the illusion that his drug testing was working , and this led to the super juiced ball of today as Manfred sought to reduce the harmful impact the expanded Zone had on pace of play and offense, which hurts attendance and ratings. If he implements strike zone changes then he may tweak the ball again and dejuice it a bit

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