When 5,304 college football fans answered researchers’ questions about their team’s greatest rival, the subset of Boston College Eagles supporters did not equivocate. The Notre Dame Fighting Irish were unquestionably their main rival.

But when Irish fans responded to the survey, they overwhelmingly identified the USC Trojans as their favorite team’s biggest rival. Second biggest? The Michigan Wolverines. Third? The Michigan State Spartans. Fourth? The Navy Midshipmen. Fifth? The Stanford Cardinal. The Eagles were sixth.

Because Eagles fans assigned 74.17 out of a possible 100 “rivalry” points to Notre Dame, and Irish fans reciprocated with just 1.71 points for Boston College, researchers B. David Tyler and Joe Cobbs identified this pairing as the “most unbalanced rivalry.”

In essence, statisticians are buttressing Irish’s fans perception of Boston College as younger brother (Fredo) who looks up to older brother (Michael Corleone).

Recognizing that both researchers and fans have different conceptions of what “rivalry” means, Tyler and Cobb hypothesized that all perceptions of “rivalry” share three core properties:

Rivalry is nonexclusive.

It is continuous in scale.

It is bidirectional, i.e. rivalry is based on perspective and not necessarily shared by opponents.

They then posted on 194 message boards looking for fans who hold strong associations with a particular team and asked them to take a 10-minute survey. (The survey is still available to fans, and the results are periodically updated.)

The respondents had the following characteristics:

77 percent attended the college of their favorite team (whether currently or in the past.)

83 percent attended at least one game per year.

85 percent had completed college.

95 percent were male.

99 percent lived in the United States

The average age of respondents was 36.8.

Here’s what they learned:

Within college football, the most common number of rivals offered was three. More than 92 percent of survey respondents identified their team having more than one rival.

Fans perceive varying degrees of rivalry. Respondents were given 100 “rivalry points” to allocate to their favorite team’s rivals. The main rival received, on average, 62 points. The secondary rival received about 24 points. The third rival received, on average, about 13 points.

When researchers focused only on rivalries where both teams’ fans generally agreed that the other is a rival (by listing the other team first or second), there was a 23 point difference — which showed a clear difference in perceived rivalry between each side.

The researchers wrote: “Textual comments illustrate that some fans recognize the potential for bidirectionality in rivalry. This realization was perhaps best exemplified by respondents who gave minimal points to an opponent, describing that opponent as the ‘little brother,’ while that opponent’s fans gave significant points to the ‘big brother.’ This familial term is part of the college football fan’s lexicon, reinforced in 2007 when Michigan’s star running back Mike Hart used the term in a press conference to refer to Michigan State.”

As for Irish-Eagles fans and other “uneven” rivalries (Vanderbilt-Tennessee, Idaho-Boise State, Oklahoma State-Oklahoma), researchers found that “big brother respondents often attempt to make it clear that they do not perceive the little brother to be a threat; if seen as a threat, that would acknowledge the opponent to be a legitimate rival and giving too many points to such an opponent would provide validation to the little brother.”

The all-time series between Boston College and Notre Dame is pretty balanced. The Irish lead, 13-9, although there’s two ways of looking at the matchup in recent years.

and yet still just 5-5 over the last 10 matchups. — Tim Stewart (@timstwrt) June 2, 2017

Of course, “little brother” has twice spoiled promising “big brother” seasons in 1993 and 2002.

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The other “uneven” rivalries are much more lopsided:

The Tennessee Volunteers have won 75 of its 111 games (.705, since six were ties) against the Vanderbilt Commodores.

The Boise State Broncos have won 22 of 40 games (.563, because one tie) against the Idaho Vandals. But the Broncos have won the last 12 matchups dating back to 1999.

The Oklahoma Sooners have won 86 out 111 games (.806, because 7 ties) against the Oklahoma State Cowboys.

The Eagles will host the Irish Sept. 16 at Alumni Stadium. Kickoff is at noon and will be broadcast by ESPN. You can learn more about the research at KnowRivalry.com or by purchasing the research paper for $19.95.