Tony Romo and the new Total QBR

SAN ANTONIO -- The folks in Bristol developed a new formula to determine just how good a quarterback is from a statistical standpoint.

Peter Keating of ESPN writes: "ESPN's analysis of nearly 60,000 NFL plays over the past three seasons. QBR looks at every facet of quarterback play, from passing and rushing to fumbling and taking sacks, and allocates credit or blame to QBs according to how each and every play they make contributes to their team's success."

Based on last year, Tom Brady led all quarterbacks with a 76 Total QBR. Tony Romo, who played only six games last season, had a 58.1 rating, good for 11th. Jon Kitna, who started 10 games, had a 46.1 rating, finishing 22nd.

The Total QBR is a replacement of sorts for the traditional quarterback rating that also uses a statistical formula.

Here's a primer on what the basics of the Total QBR are:

Scoring: 0-100, from low to high. An average QB would be at 50.

Win Probability:All QB plays are scored based on how much they contribute to a win. By determining expected point totals for almost any situation, Total QBR is able to apply points to a quarterback based on every type of play he would be involved in.

Dividing Credit:Total QBR factors in such things as overthrows, underthrows, yards after the catch and more to accurately determine how much a QB contributes to each play.

Clutch Index: How critical a certain play is based on when it happens in a game is factored into the score.

Go here for a complete list of the best quarterbacks based on the new Total QBR from 2008-10.