There are three questions which I am asked frequently about certain decisions that were made in assembling the winning percentage database:
The NCAA's official method of computing winning percentage is, in essence, to count a tie as half-a-win plus half-a-loss.
If a team has W wins,
L losses, and T ties, their winning percentage is defined by
the NCAA as {(W+[T/2])/(W+L+T)}.
A record of 6-1-3 is therefore
scored as "{(6+[3/2])/(6+1+3)}"...
or as if it were 7.5 wins out of
10 games.
Thus, a record of 6-1-3 is a
winning percentage of 0.750
(7.5/10).
It is not 0.857 (6-1), as
if ties were dropped from the computation entirely.
It is not 0.600 (6-4), as
if ties counted as losses.
Someone at the NCAA told me that the NCAA's statistics count "NCAA-imposed" forfeits but "self-imposed" ones. Some resources such as The College Football Scorebook chose not to recognize forfeits at all. Why do I count forfeits?
As I see it, on one hand we have the desire to allow the records reflect the on-the-field result, and on the other hand we don't want to include results in the records which are not really legitimate. In my opinion, the latter overrules the former; if a team elects to forfeit a given game, then the database will be changed to reflect that. Most forfeits happen because an ineligible player was used. It's not really fair to count the actual result, thus penalizing the loser for the winner's failure to follow the rules.
I try to place a note on the team's all-time records page indicating the reason for the forfeit and the record before the forfeit. (This allows people who are browsing the year-by-year data for any given team to see both versions of the team's record.) But the pre-forfeit record is not used when winning percentage is calculated.
The official NCAA all-time record for Nebraska has seven less wins than my own data. The reason is that a seven-game series with Lincoln High School (in 1899-1905) is not counted in the NCAA statistics.
Some folks have implied that the NCAA refuses to count those games, but that is not really the case. What happened (as far as I can tell) is that Nebraska considers those games to be "exhibition" contests and does not include them in the results which they report to the NCAA. The NCAA did not exist when those games were played (it was formed in 1906 as the IAAUS), and I don't believe the NCAA makes rulings on games prior to that point. (In fact, the NCAA doesn't seem to make rulings on many equally questionable games after that point as well, as we shall see...)
Even once the NCAA existed, they didn't start encouraging the best teams to play decent opposition until about 1920. Prior to that, and in many cases up to World War II, there are a lot of games against opponents that could be considered "exhibition contests." For example, what are we to make of the University of California's game against a group of their own alumni in 1923? Or the University of Washington's game against the crew of the U.S.S. Oklahoma in 1925? Or Ohio State's game against the Dayton YMCA in 1892? How about Southern Cal's 1907 season where half of their opponents were high schools? In my opinion none of these opponents are really any more credible than Nebraska's, and yet all of these games are counted in the NCAA totals.
Basically, my opinion is this: (1) in the early days of the sport nearly everyone played a lot of opponents that wouldn't be considered credible today; (2) it's not really fair to let some teams keep those games in their record while not allowing others to do so; and (3) just trying to judge which games are really "exhibition contests" is a big can of worms that I don't want to open.
So my policy is just to count EVERY game, even if the school in question does not.