The Dallas Cowboys and "best offensive line" have been synonymous with one another the past few seasons. It's a claim that's no longer a hot take because it's mentioned so often.

But why are they considered to be the best in the NFL? Pro Football Focus' Mike Renner tried to figure that out recently. Here's what he came up with:

"It's a unit that blocked for castoff running backs and quarterbacks the majority of last season, yet still came away as PFF's highest-graded pass-blocking and run-blocking line," Renner said. "Unlike some recent top offensive lines -- like the 2012 San Francisco 49ers and the 2013 Philadelphia Eagles -- the Cowboys aren't doing it with anything innovative or different. They simply execute far better than any other team in the league."

Renner said having players like Tyron Smith and Travis Frederick help.

"It starts with not having any weaknesses along the offensive line," he said. "La'el Collins was their lowest-graded starter, and he still ranked only 43rd out of 66 starting guards last season. They combine that high floor with freakish top-tier talent. Everyone knows about left tackle Tyron Smith's dominance. Our highest-graded tackle last season, he can move like a tight end."

He also said that he made a realization about the Cowboys by looking at their line.

"The more I reviewed the Cowboys' 2015 performance, the more I understood why they were willing to eschew conventional wisdom by taking a running back -- Ohio State's Ezekiel Elliott -- in the top five of the draft. They gave their backs a clean run to the safety-level far too often to only average 4.7 yards per carry as a team. Getting a running back who combines vision with elusiveness and power will be a huge boon for the Cowboys' offense. The scary thing is that, with four starters at 25 years of age or younger, the unit could realistically be even better in 2016."

To view Renner's full article, as well as him breaking down the Cowboys' favorite two running plays, click here.