One of my annual traditions is looking at quarterbacks who attained a passing efficiency of 160 or above, with the reason being that it's very difficult to hit that level of play. I'm not sure why I neglected to cover the topic last year, but I did it in 2011, 2012, and 2013. I'll just have to make this update cover two years' worth.
Though in 2013 we saw 11 quarterbacks hit 160, typically fewer than 10 manage it in any given season. It's becoming more common thanks to high efficiency spread passing schemes, but as recently as 2002 no quarterback managed a PE of 160. Of those who do manage to hit that mark, many don't return thanks to graduation or jumping to the NFL. The 2012 season had a high of seven QBs with PEs of 160 who would return the next year, but no other season since 2000 has had more than four.
Since the last update two years ago, two important things have happened. First, Tajh Boyd became the first quarterback since 2000 to hit 160 as a junior and then improve his mark the following year as a senior. In 2012, he posted a passing efficiency of 165.58 and improved it by 3.1 to 168.68 as a senior in 2013. You might call that being roughly even, and I wouldn't argue too much there. Still, I don't want to withhold credit given that no one else has managed to improve on a 160+ passing efficiency as a senior.
The other big event was Marcus Mariota joining Kellen Moore and Tim Tebow as the only quarterbacks in the last 15 years to log a passing efficiency of over 160 three times. He posted a 163.23 as a freshman in 2012, 167.66 as a sophomore in 2013, and 181.75 in his Heisman winning junior campaign.
Teddy Bridgewater and Andrew Luck are examples of players who had a chance to go three in a row but who left for the NFL rather than go for it, while injuries derailed Sam Bradford's opportunity at it. Only Mariota and a hypothetically injury-free Bradford would have had a chance to go four-for-four, but both went to the NFL after their junior seasons.
Meanwhile we got to see some great examples of why it's so tough to hit 160 multiple times. Aaron Murray got there in 2012 with a 174.82, but an injury plague around him in the offensive unit helped limit him to 158.82 in 2013. That he still almost got there is impressive, but things outside his control hampered him. Injuries to the player himself can strike, as Oklahoma State's J.W. Walsh (170.11 in 2012) and Bowling Green's Matt Johnson (161.73 in 2013) failed to appear in enough games the following year after going 160+ to qualify for statistical standing. One player who did manage a repeat was AJ McCarron, who suffered the customary junior-to-senior drop but did manage 167.16 in 2013 after 175.28 in 2013.
Two of the four 160 guys from 2013 who returned simply couldn't keep up their prior paces. Jameis Winston fell from 184.85 to 145.53 thanks in large part to some ghastly interception numbers, and Bryce Petty went from 174.29 to 157.83 despite nearly leading his team into the College Football Playoff.
In 2014, only six players managed to hit a passing efficiency of 160 or higher. Two of them aren't returning, Colorado State's Garrett Grayson was a senior and Mariota went to the draft.
You should be familiar with at least two of the four returners. USC's Cody Kessler is one of them, and he is one of the big reasons why the Trojans are likely to be a top five or ten team in the preseason polls. The team has talent aplenty, but he may fail to hit 160 again with three of his top four pass catchers gone—including 1,300-yard receiver Nelson Agholor and nearly 1,500-yard rusher Buck Allen. He also has working against him that Boyd was the only one of 14 past juniors to return as seniors and improve upon their passing efficiency scores.
Ohio State's J.T. Barrett is another, but there's no guarantee he'll even start this year. He's locked in a battle with Braxton Miller and Cardale Jones, and there's no telling right now who will take the lion's share of the snaps in Columbus this year.
The third is a guy you've never heard of, Zach Terrell from Western Michigan. I can't say I know a thing about him, but non-power conference quarterbacks from outside Boise State don't have a great track record of maintaining 160 passing efficiencies. Toledo's Bruce Gradkowski did it in both 2003 and 2004 before falling off in 2005, but Marshall's Byron Leftwich (2001, but not 2002), Hawaii's Colt Brennan (2006, but not 2007), Toledo's Terrance Owens (2011, but not 2012), and San Jose State's David Fales (2012 but not 2013) couldn't duplicate their passing efficiency marks of 160 or above.
The fourth is WKU's Brandon Doughty, who technically was a senior last year but who got a sixth year of eligibility last December. He has a real chance to repeat thanks to playing in Jeff Brohm's high powered passing offense. He'll have plenty of attempts, we know that at least.
In the end, quarterbacks since 2000 that logged a passing efficiency of at least 160 saw their PEs drop by an average of 12.6 the following seasons. Of the 36 opportunities to improve, only Moore, Mariota, and Bridgewater each going from their sophomore to junior seasons managed to bump up their passing efficiencies by more than 10.
This should make sense. The longer a quarterback plays, the more film there is to pick up on his tendencies. Plus, the regular churn of not just players but also coaches in college football means that the winning formula that led a player to get above 160 is not guaranteed to be around from one year to the next. After posting marks of 161.8 and 170.8 in his first two seasons, Rex Grossman saw the largest single fall of any of these guys with his passing efficiency plummeting 49.3 to 121.5 after going from Steve Spurrier to Ron Zook and Ed Zaunbrecher.
That's an extreme example, but things happen. Tebow suffered in 2009 without Dan Mullen and Percy Harvin. Winston missed Kelvin Benjamin and Kenny Shaw in 2014. Kessler will miss Agholor and Allen this year. As I mentioned above, Murray dealt with an injury plague in 2013.
Simply hitting a passing efficiency of 160 is a difficult thing that most quarterbacks never accomplish. Doing it more than once is truly remarkable.