Sunday, May 24, 2009

Joe DiMaggio - Thoughts on the Streak!

What are the odds of Joe DiMaggio's 56 game winning streak?

This week I received my Spring 2009 copy of CHANCE magazine from American Statistical Association. Don M. Chance wrote an excellent article evaluating hitting streaks in general but also looking at factors why Joe DiMaggio may have accomplished such a feat.

Of the top 50 all time hitters Chance identified Ty Cobb, Ed Delahanty and Willie Keeler as being the top three most likely to accomplish a 56 game hitting streak. Ironically none of these hitters did it. In fact the author points out that of those hitters who achieved a streak of 30 games or more (including DiMaggio), none of these players were in the top 100 hitters of all time.

Earlier this year in the NY Times Samual Arbesman and Steven Strogratz presented results of a simulation study involving Monte Carlo style analysis of 10,000 baseball universes. The most frequent streak was 51 games. The median streak was 53 games. Two thirds of the time the record streak was found to be between 50 and 64. So Joe DiMaggio's streak was to be expected in the normal course of baseball history. It was not an unusual event.

The question that cannot be answered yet; why did Joe DiMaggio accomplish this feat instead of one of the top hitters of all time? According to Don Chance, Ty Cobb had a 1-204 chance of accomplishing this streak. He was about four times more likely than DiMaggio who has been estimated to have had only a 1 - 826 chance in his career.

The factors that the study cannot address are the intangibles. The play of the Yankees at the time of the streak. Teams that do well encourage success among all the players and create situations where perhaps a streak can occur. If the team is hot the players are hot. Most of these analysis assume independence of each batting opportunity. However, if a player is in a streak is his hitting actually independent. Can the likelihood of a hit be greater if the player is hot or in the zone than at other times. What about pitching? How does average opponents pitching play into the probability of a streak.

In conclusion, we just don't know why it was Joltin' Joe who set the record. Don Chance, Samual Arbesman and Steven Strogatz have done some excellent statistical analysis of streaks and should be commended for the information. Joe DiMaggio was an excellent personality remembered for his popularity on the field and off the field.
Post a Comment