Tom Brady led the Tampa Bay Buccaneers to a team-record 34-0 halftime lead on Saturday at Detroit, completing 22 of his 27 passes for 348 yards, four touchdowns and no interceptions. The Buccaneers then let Brady rest in the second half as they cruised to a blowout 47-7 win.
Those numbers combined to give Brady a 158.3 passer rating on Saturday, which is as high as that scale goes. This is a rare accomplishment best demonstrated by this combination of notes: that marked just the third time that Brady has finished a game with a perfect passer rating and those three perfect games are as many as any quarterback has thrown in NFL history.
The passer rating formula uses four statistics and a chart that kicks out a certain number based on how the quarterback fared in each one. The four elements of passer rating are completion percentage, yards per pass attempt, touchdowns per pass attempt and interceptions per pass attempt. There is a certain point at which going higher on any of these four scales doesn't improve the passer rating; for example, both 80% and 90% completion rate will kick back the same number.
To finish with a perfect passer rating, a quarterback must complete at least 77.5% of his passes, average at least 12.5 yards per attempt, have a touchdown percentage of at least 11.875% and throw no interceptions. Brady's figures in each category on Saturday, in that order, were 81.5%, 12.9, 14.815% and zero.
Brady's marks in the first three categories were all his best so far as a Buccaneer, by far. His previous best completion percentage was 73.3% in the Week Seven win at Las Vegas; his previous best yards per pass attempt was 8.7% in the Week 10 win at Carolina; and his previous best touchdown percentage was 10.870% in the Week Four win over the L.A. Chargers. So, yeah, it was his best game as a Buc so far.
None of the above has anything to do with the NFL's Next Gen Stats, which have only been recorded and published since 2015. The league has been generating and publishing the passer rating statistic since 1973, and of course it can be applied to earlier games by just plugging in statistics.
What Next Gen Stats do tell us is that Brady probably shouldn't have pitched a perfect game, or at least the passes he collectively threw didn't have that expected outcome. To be fair, some of that can probably be attributed to the Lions' depleted defense and coaching staff, but Brady still completed more passes than the Next Gen data collection expected him to complete.
Next Gen assigns a completion probability to every pass based on such factors as receiver separation from the nearest defender, the receiver's location on the field, the amount of space the quarterback had from the opposing pass-rushers, and more.
Applying that data to each of a quarterback's passes, Next Gen comes up with his "xCOMP," or Expected Completion Percentage. From there, it's just a matter of comparing that xCOMP to how many passes the quarterback actually completed and seeing how much better or worse he was than expected. That's Completion Percentage over Expected, or "CPOE."
Brady was a lot better. The Next Gen calculations had Brady's CPOE at +18.4, which is the best he has compiled in any first half this season. A lot of that had to do with accurate deep-ball passing. Next Gen identified seven of his throws as deep balls (in the air 20 or more yards downfield) and he completed five of them for 162 yards and two touchdowns.
One of Brady's best completions was a 27-yard touchdown to Mike Evans in the first quarter. Next Gen defined Evans' pattern as a "go route" and says that is the 13th time he has scored on that route since 2018, the most by any player in the NFL. The ball traveled 41.5 yards in the air (factoring in Brady's drop, Evans distance into the end zone and the angle) and had a completion probability of just 24.9%.
So we already knew that Tom Brady was very good on Saturday in Detroit, and by the estimation of passer rating, he was actually perfect. According to Next Gen Stats, Brady was better than we even should have expected.