Before we get into the ratings system itself, let's look at how the system progressed from a pee-wee player into the professional it is today. The current rating system has been in place since 1973, but it has gone through a lot of changes. Some form of the system has been around since the early 1930s, when the only statistic kept was total passing yards. Through the years, stats were added to the list or taken away, with some years looking at a total of six different figures and other years having only one number to rely on.
The major problem with these older systems is that they all relied on numbers from other quarterbacks to make any sense. In other words, all the quarterbacks were judged against the group instead of each player being rated on an individual basis.
In 1971, Don Smith was working as an executive with the NFL Pro Hall of Fame. Quite the statistician, Smith began working on a system that would rate a quarterback based on his performance only. The new system, put into place in 1973, is based on four major factors (see sidebar) of a passer's game and will net a result that is roughly on a scale of zero to 150. Another advantage of the new system is that it can be used retroactively on all previous players. That allows the National Football League to compare quarterbacks from the early days of the game to those playing today [source: Don Steinberg].
Now that we know the history of the system, let's move on to discussing the Xs and Os of the formula. Click to the next page to find out how the rating is actually computed.