Much of the credit for the remarkable rise of the Dallas Cowboys from 4-12 last season to 13-3 this season has gone to two rookies: quarterback Dak Prescott and running back Ezekiel Elliott.

But insiders will tell you that the real secret to the Cowboys’ success is their offensive line, which, by most accounts, is the best in the N.F.L. Whether blocking for Elliott or giving Prescott the time he needs to find an open receiver, Dallas’s dominant line is the constant that has driven the team forward.

It is difficult to scientifically assess the merits of an offensive line. Linemen do not compile straightforward statistics, like yardage or touchdowns. But measures that do exist point to the Cowboys’ line as elite.

Three of the five starters have been chosen to the Pro Bowl, a total matched only by the Oakland Raiders. It is the fourth consecutive Pro Bowl selection for left tackle Tyron Smith and the third straight for center Travis Frederick and right guard Zack Martin.