My general theory is that HFA matters most to teams closest to the middle of the conference. The reason is hard to explain so I'll use an illustration, the
current B1G Power Rankings.
Assume, for the sake of this discussion, that the Power Rankings are exactly accurate. I think we would all agree that HFA is almost certain to be irrelevant in a game between #1 Wisconsin and #14 Illinois. Similarly, we would all agree that HFA is likely irrelevant in games between #2 Ohio State and #13 Rutgers or #3 MSU and #12 Indiana.
I would suggest that HFA is reasonably likely to be decisive in games between teams within 2-3 spots of each other. Ie, in the hypothetical games above I would pick UW over IL, tOSU over RU, and MSU over IU regardless of location. However, if #1 Wisconsin and #2 Ohio State were to play this year I would pick the home team. I would also at least consider picking the home team in games between #1 UW and #3 MSU or #1 UW and #4 PSU.
Based on the above paragraph, teams #4 through #11 each have six potential games in which HFA is likely to be decisive:
- For #4 HFA is likely to be decisive in games against #1 - #3 and #5 - #7.
- For #5 HFA is likely to be decisive in games against #2 - #4 and #6 - #8.
- . . .
- For #11 HFA is likely to be decisive in games against #8 - #10 and #12 - #14.
Teams #1 - #3 and #12 - #14 have less potential games in which HFA is likely to be decisive:
- Teams #1 and #14 only have three potential games in which HFA is likely to be decisive, games against #2 - #4 for #1 and against #11 - #13 for #14.
- Teams #2 and #13 have four potential games in which HFA is likely to be decisive, games against #1 and #3 - #5 for #2 and against #14 and #10 - #12 for #13.
- Teams #3 and #12 have five potential games in which HFA is likely to be decisive, games against #1 - #2 and #4 - #6 for #3 and against #13 - #14 and #9 - #11 for #12.
IMHO, my theory matches up reasonably well with the date presented by
@Hawkinole in this thread's OP. Minnesota, Purdue, and Iowa have the largest Deltas indicating that HFA is a relatively bigger factor for them. That makes sense because over the whole history of the those teams it seems to me that those are teams that have only rarely been the best or the worst in the conference. Similarly, ILL, UNL, and NU have the smallest Deltas indicating that HFA is a relatively smaller factor for them. That makes sense because Illinois is somewhat Jeckyll and Hyde in that when they are good they tend to be REALLY good (see for example 1983 when they were the only team to ever beat every other BigTen team in a single year) and when they aren't good they tend to just plain suck. Similarly, Nebraska over that time-frame was generally the best or at least one of the top-2 teams in their conference and Northwestern was typically the worst or one of the worst teams in the BigTen and Big11Ten.
