Seventy years ago today, Joe DiMaggio went 1-for-4 as the New York Yankees lost 13-1 to the Chicago White Sox. Nobody knew at the time that DiMaggio's lone hit in a dreary May blowout would turn out to be the beginning of a two-month run that would result in DiMaggio holding one of the most treasured records in the history of baseball.
To almost anyone with interest in baseball, 56 is an instantly recognizable number, entirely associated with the 56 consecutive games in which DiMaggio had a hit. Other treasured numbers, 714 or 755 or 61, have already fallen to new record holders, but 56 remains. There are other records that have existed for even longer, but they've either failed to capture the public's imagination -- neither Earl Webb with 67 doubles or Chief Wilson and his 36 triples have enough pizzazz to match the player that married Marilyn Monroe -- or reflect an era of baseball that would be foreign to today's fans. When it comes down to it, the most exciting records are those that could plausibly be broken, so we enter into seasons wondering if this is the year someone will catch DiMaggio, not wondering if someone will top Jack Chesbro's 41 wins in 1904.
In the past 70 years, just three players have even come within 20 games of DiMaggio's record: Pete Rose, Paul Molitor and Jimmy Rollins. It sounds so easy on paper -- plenty of players have had seasons in which they got hits more often than DiMaggio, but most runs at the record end up a month short.
So just how unlikely was DiMaggio's run? To get an estimate of the likelihood of DiMaggio getting hits in those 56 consecutive games, first I calculated an estimate of what his ability level was at the time. "True talent" is one of the more abstract concepts in sabermetrics, and in truth, it no doubt varies from game to game and we never get to find out what the real answer is. But we can make an educated guess. To get a baseline batting average for DiMaggio, I took all his seasons from 1939-1942, translated them into a 1941 offensive context, with 1941 given greater weight. I came up with a .350 baseline for DiMaggio's expected batting average.