(Bump. -- Ed.)
I had considered posting this shortly after the 4th win in a row over UM, when many of the UM fans were stating that it still wasn't a rivalry with MSU. Their true "rival" was OSU, which had in fact dominated them for the better part of the last 10 years. But this week's loss to UM and the increased discussion of "The Rivalry" made me dust off the data, apply a few more filters, and come to the conclusion that there is a true rivalry with MSU/UM.
I took the win-loss and home/away records from the very first varsity game played against UM. Source was the MSU historical records as published in football game programs.
Interesting Fact: MSU played UM 3 times as a JV team. Lost quite handily in all 3. Those games are not counted.
MSU wins were scored a 1, UM wins a -1, and ties a 0. I then created 3 rolling averages: 10 year, 17 year, and 25 year. I chose these based on typical perception cycles. If a team dominates the other over a span of 10 years, it starts to change the collective perception of either team. I chose 17, since that is the typical age of a HS recruit, when they are making their decisions about what school to choose, and may elect a "winning" team vs. a "losing" team . And 25 was chosen to reflect the longer memory and generational impact - your dad's Spartans and your Spartan's aren't the same team.
I then graphed the results to get a visual look.
If the rolling average is above 0.75 or below -0.75, the team with the average on their side can be said to be "owning" the other, and isn't much of a rivalry. Between 0.25 and 0.75 on the high end of the index, or between -0.25 and -0.75, is a middle ground that shows dominance by one team but indicates that the tide may be turning, depending on consecutive wins/losses. But if the rolling average is between 0.25 and -0.25 (close to 0), then neither team has a distinct advantage, and there is a significant increase in give-and-take of wins and losses, leading to a rivalry, when either team can win and contests are more hotly debated.
Interesting Fact: In 2010, Both 10 year and 17 year lines crossed into the 0.25>0<-0.25 "Rivalry Zone". In 2011, the 25 year line did as well, the first time when all 3 lines were in the Rivalry Zone since 1975. (Coincidentally, my birth year.) The only other time that all three lines were in this zone was 1958. Further, all three lines starting trending up in 1949, the year before we joined the Big Ten, and by 1953, when we started athletics in the Big Ten, all three were very close to the zone.
But let's go one step further. UM holds an overall advantage in the series, 67-32-5. But what they seem to overlook is that they have a HUGE advantage in where the game is played, as more than twice as many games have been played in AA vs. in EL (71-33). One would expect them to have a better winning percent based on the fact that they played at home much more often. I'll let you figure out what to deduce from this. (Mine is something along the lines of that this is proof of the arrogant bastardry of UM, in they would refuse to play in EL.)
Interesting Fact: Between 1910 and 1952, the teams met 41 times, 37(!) of them in AA, and only 4 times in EL.
So using a factor of 0.667 (figuring that you would expect to win 2 out of 3 home games), UM's expected win total was 47, vs. an actual win total of 48. Not an overwhelming domination, as they would have you believe. MSU's expected win total in EL is 22 vs. and actual of 12. (Ties aren't included in this). To their credit, UM teams have fared well in road wins vs. expected. UM's expected win total in EL is 11, vs. an actual of 19. MSU's expected win total in AA is 24 vs. actual of 20.