At the end of the Lions’ win over the Seahawks on Monday night, Troy Aikman mused on ESPN about how the NFL’s official passer rating system could possibly give Jared Goff something other than a “perfect” passer rating for his efforts. The reason has to do with the touchdown pass that Goff caught, but didn’t throw.

As a team, the Lions went 19-for-19 passing for 273 yards, with three touchdowns and no interceptions. That translates to a perfect passer rating of 158.3. But so does the touchdown pass Amon-Ra St. Brown threw to Goff on a trick play. Individually, Goff completed 18 of 18 passes for 292 yards, with two touchdowns and no interceptions. That means he threw a touchdown on 11.1 percent of his passes, and that’s simply not “perfect” for passer rating purposes.

To finish a game with a perfect passer rating, you must throw at least 11.875 percent of passes for touchdowns, with no interceptions, a 77.5 percent completion rate, and at least 12.5 yards per attempt. Goff managed three of those four, but fell just short on touchdown passes, meaning Goff’s passer rating for the game was 155.8. If the Lions, instead of calling the pass to Goff, had called a pass for Goff to throw a touchdown, Goff would have finished the game with a perfect 158.3.

Passer rating has been the NFL’s official passer ranking metric for more than half a century, and there’s no indication it’s going anywhere. It’s far from the best way to rank quarterbacks, in part because those arbitrary cutoffs, like a touchdown percentage of 11.875, are “perfect.” But it’s what the NFL uses, and that’s why it draws so much attention from fans and the media.

The Lions are the 57th team in NFL history to finish a game with a perfect 158.3 passer rating, and the second team to do so this year, following the Cardinals in week two. It was a historic night for Goffeven if the passersby rating system says he wasn’t perfect.