27th June 2008
Reader WillyB asked about historical rates of 2-homer games vs 2-triple games, these being performances by individual players in the games, as opposed to total by each team.
Using the batting game finder, I generated the data for the following graph:
First, here is a description of what you are seeing. For each year, I found the total number of times a player had two homers in a game as well as the total number of two triples in a game. Then, I divided by the total number of team games played that particular year. So any given game counts twice--once for each team involved. So this tells you that the incidence of 2-homer games peaked around year 2000 at roughly 7% of games. So on a day when all 30 teams played, on average 2 different guys had 2-homer games. Jeez.
For triples, I went ahead and multiplied the data by 10 just so it would be on a similar scale to HRs, but in your mind you need to divide by 10. Incidence of 2-triple games peaked around 1960 not at 6%, but rather at 0.6% of games. This means that any given team playing a full 152-game season might see, on average, one two-triple game from one of its players per season. By 2000, the rate bottom out around 0.2%, meaning roughly a team would see one of its guys have two triples in a game roughly once every 3 seasons on average.