Eli Manning ranks 2nd in the NFL in completion rate with a remarkable 74.2% average. Houston’s Deshaun Watson, on the other hand, ranks 27th out of 34 qualifying passers with a 62.2% completion percentage. But that’s a bit misleading, because as I’ve written about before, first down percentage is a much more important metric than completion percentage.

For Watson, 62 of his 92 completed passes have gone for a first down, meaning just 33% of his completed passes didn’t pick up a first down. For Manning, just 53 of his 112 completions have gone for a first down, which means a whopping 53% of his completions didn’t pick up a first down.

Completion percentage is supposed to measure how consistent a quarterback is at making positive plays. A better formula than (completed passes/pass attempts) is (first downs gained via the pass / [pass attempts + sacks] ). In other words, the numerator should be passing first downs, not completed passes, and the denominator should include sacks.

Do that for the Giants and Texans, and you see a pretty big chance. New York has picked up a first down on 32% of all passing plays this year, while Houston has done so on 38% of all passing plays. The graph below shows where each team ranks in two metrics: first downs per pass play, on the X-Axis, and completion percentage, on the Y-Axis. The two black lines show league average; this means to the left of 33.4% on the X-Axis means a team is below average at picking up first downs, and under 65.5% on the Y-Axis means a team is below average in terms of completion percentage.

The two biggest outliers are the Giants and Texans. New York is second in completion percentage, but noticeably below average at gaining first downs. Houston is solidly above-average at gaining first downs, but below average in completion rate. The teams in the upper left box are going to be overrated when you look at completion percentage (Giants, Bears, Eagles, Colts), while the teams in the bottom right box will be underrated (Houston being the clearest example).



Finally, here’s the full data set. Here’s how to read the table, using the Rams as the example. Los Angeles has completed 97 of 135 passes for a 71.9% completion rate, which ranks 3rd. The Rams have 64 first downs, so LA is averaging a 1st down on 66% of its completed passes, which ranks 3rd. The Rams have 5 sacks, which means the Rams have picked up a first down on 45.7% of all passing plays, the best rate in the NFL. The table is sorted by first downs per passing play, which is the most important stat in the table:

Tm Cmp Att Cmp% Cmp% Rk 1stD 1D/Cmp 1D/Cmp Rk Sk 1D/PP 1D/PP Rk Los Angeles Rams 97 135 71.9% 3 64 66% 3 5 45.7% 1 Tampa Bay Buccaneers 103 149 69.1% 8 68 66% 2 9 43% 2 Los Angeles Chargers 100 147 68% 11 62 62% 5 6 40.5% 3 Atlanta Falcons 99 145 68.3% 10 60 60.6% 9 10 38.7% 4 Carolina Panthers 64 95 67.4% 13 39 60.9% 8 6 38.6% 5 Kansas City Chiefs 90 138 65.2% 18 55 61.1% 7 5 38.5% 6 Cincinnati Bengals 103 157 65.6% 17 63 61.2% 6 7 38.4% 7 Houston Texans 92 148 62.2% 25 62 67.4% 1 17 37.6% 8 Minnesota Vikings 131 189 69.3% 7 74 56.5% 14 13 36.6% 9 Jacksonville Jaguars 97 150 64.7% 19 57 58.8% 11 6 36.5% 10 Oakland Raiders 120 169 71% 4 64 53.3% 18 8 36.2% 11 New Orleans Saints 123 163 75.5% 1 61 49.6% 22 6 36.1% 12 Pittsburgh Steelers 119 186 64% 20 70 58.8% 10 9 35.9% 13 Washington Redskins 66 96 68.8% 9 36 54.5% 15 6 35.3% 14 Detroit Lions 114 171 66.7% 14 62 54.4% 16 6 35% 15 San Francisco 49ers 76 126 60.3% 29 48 63.2% 4 14 34.3% 16 Miami Dolphins 70 100 70% 5.5 37 52.9% 19 8 34.3% 17 Baltimore Ravens 111 175 63.4% 21 63 56.8% 13 10 34.1% 18.5 New England Patriots 121 179 67.6% 12 63 52.1% 20 6 34.1% 18.5 Chicago Bears 91 130 70% 5.5 45 49.5% 23 10 32.1% 20 Tennessee Titans 78 124 62.9% 22 42 53.8% 17 7 32.1% 21 New York Giants 112 151 74.2% 2 53 47.3% 28 15 31.9% 22 Indianapolis Colts 163 246 66.3% 16 79 48.5% 25 10 30.9% 23 New York Jets 73 127 57.5% 30 42 57.5% 12 10 30.7% 24 Denver Broncos 87 141 61.7% 27 42 48.3% 26 9 28% 25 Dallas Cowboys 71 115 61.7% 26 36 50.7% 21 14 27.9% 26 Philadelphia Eagles 113 170 66.5% 15 50 44.2% 31 14 27.2% 27 Green Bay Packers 103 164 62.8% 24 48 46.6% 29 14 27% 28 Seattle Seahawks 76 121 62.8% 23 36 47.4% 27 16 26.3% 29 Cleveland Browns 79 148 53.4% 31 39 49.4% 24 16 23.8% 30 Arizona Cardinals 69 114 60.5% 28 27 39.1% 32 8 22.1% 31 Buffalo Bills 60 121 49.6% 32 27 45% 30 21 19% 32 NFL 3071 4690 65.5% 1674 54.5% 321 33.4%

From a historical perspective, the Bills 19.0% rate is absurd. Since 1970, just two teams — the 1975 Saints (18.4%) and 1977 Bucs (18.7%) have ever finished a season with a rate lower than 19%. The fact that a team in 2018 could match the poor numbers from the dead ball era is remarkable. The best rate in history came from the 2004 Colts at 44.0%; the Rams are currently ahead of that, of course, but it’s only been four games. Since 1999, the three best rates in terms of passing first downs per pass play through four games belong to the 2013 Broncos (47.0%), 2000 Rams (45.8%), and 2018 Rams (45.7%).