Science Versus Opportunity: 4th Quarter Completion Percentages for Two Young Quarterbacks

Last Tuesday leading up to Week 10 in the NFL, Nate Ravitz (of ESPN and Fantasy Football Focus Podcast) tweeted:

The tweet sparked a comparison between the two players.  There wasn't really a jumping off point until two people asked about each QB's fourth quarter completion percentages. This seems more interesting than just completion percentage when measuring both quarterbacks against each other because the stat could potentially explain how well each QB finishes a game. I went through each game through Week 10 for each quarterback, and here's what the data revealed:

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As it turns out, Newton and Luck are very similar in completion percentage in the fourth quarter; Cam at 58.97% and Luck at 57.63%. The table shows their touchdowns and interceptions to be similar too, but Luck has attempted more passes and has more completions and yards as a result. What is not shown on the table is that each quarterback also has one rushing touchdown in the fourth, and Luck has also passed for a two point conversion.

And if you're looking for a QBR for each player based on their fourth quarter stats only, you can add everything in the table up yourself, or you can check out this awesome page by the talented team at Sporting Charts.  Note that they've calculated the fourth quarter QBR for each team, as opposed to each quarterback though. This just means their data isn't unusable if you're looking for a fourth quarter QBR for Christian Ponder or Brian Hoyer, since multiple quarterbacks have started for the Vikings and Brown.  Fortunately, with the Newton and Luck comparison, their back-ups have rarely taken a snap at all and if they have in the fourth its been to hand the ball off or kneel down almost exclusively.  I think Derek Anderson has thrown one pass this year, so my point is that the back ups are not skewing the data in a noticeable way.  The numbers for each quarterbacks Total QBR and Fourth Quarter QBR look like this:

Carolina Panthers: Total QBR = 88.3, 4Q QBR = 77.3

Indianapolis Colts: Total QBR = 86.1, 4Q QBR = 69.1