The skeptics have been proven right so far this season in refusing to believe that Khris Davis’s batting average was permanently fixed at .247 by some supernatural force. After hitting exactly that in each of the past three seasons, Davis appears to have broken free of the .247 spell: He’s hitting .248.
Baseball’s measure of hitting success has always been rounded to the third decimal. Technically, the Oakland Athletics outfielder has hit .2474489796, .2468468468 and .2473498233 respectively from 2015 to 2017, and this year his average is all the way up to .2484848485. In his only other year of at least 350 plate appearances (2014), he hit .2435129741, or .244. Regardless of how you round these numbers, they make Davis the most consistent hitter in baseball history over any five-year stretch. The total movement of his three-digit average — calculated by simply adding the absolute differences from season to season across five years — is just 4 points (that’s .004 in nonbaseball speak). And the average movement of his average is an absurdly low four-fifths of a point per season.
|YEARLY Batting Average|
|span||Year 1||2||3||4||5||total Movement|
According to Fangraphs, none of the 21,214 other qualifying five-year periods1 is even close. Journeyman outfielder Nori Aoki had a total movement of 9 points between 2012 and 2016, which comes in second but is still more than double Davis’s. And only one other hitter in history finished with the same average in three straight years — Mookie Wilson for the Mets, hitting exactly .276 from 1983 to 1985.2 Just 178 hitters have had the same rounded average in two consecutive seasons.
To get a better sense of how bizarre Davis’s consistency is, consider FanGraphs’s finding that batting average does not even stabilize until 910 at-bats. (By “stabilize,” we mean getting to the point at which a player’s batting average is roughly halfway explained by his own skill, with the other half still owed to random variance.) Of course, batters never get 910 at-bats in a 162-game season, which is why batting average has typically been the bane of projection systems. Incredibly, a player’s current batting average is actually a poor predictor of his future batting average even in the same season, never mind from season to season.
So wild swings are perfectly normal. The average movement for the entire sample is about 100 points in every five-year period. A perfect example of average variance in the category is Babe Ruth from 1930 to 1934, when he hit, consecutively, .359, .373, .341, .301 and .288.
But in 2018, we are witnessing history in batting average on both sides of the spectrum. The exact opposite of Davis is Bryce Harper of the Nationals. He’s tied as the third most volatile hitter ever over a five-year period. Harper’s roller coaster ride in the statistic has taken him from .273 in 2014 to .330 in 2015, back to .243 in 2016 then up to .319 last season. This year, Harper is down to .214. That represents a total movement of 325 points. Harper was bested in extreme variance only by Brooklyn Dodger Hall of Fame catcher Roy Campanella, who had a 358-point swing from 1952 to 1956 and a 338-point swing from 1953 to 1957, and King Kelly of the Chicago White Stockings and Boston Beaneaters, who had a total movement of 331 points from 1883 to 1887. Kelly is also in the Hall of Fame, and Campanella was a three-time National League MVP, an award Harper won unanimously in 2015.
|Yearly Batting Average|
|Span||Year 1||2||3||4||5||TOTal Movement|
So a lack of consistency doesn’t imply that a hitter is bad — though you may not want to invest in him in your fantasy baseball leagues just on the basis of last season’s numbers. The people who “owned” Kelly when he hit .288 in 1885 between two years leading the National League in hitting with an average north of .350 doubtlessly took a bath in their hypothetical, old-timey roto leagues. Harper’s owners this year are echoing their pain, 133 years later.
But Davis is Mr. Reliable. You expect .247 and he gives you .247 — or maybe .248. At worst, .244. Davis is a beacon of consistency in what’s otherwise a wilderness of batting average randomness.
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