By the numbers: Debating the ACC's best cornerbacks

Who’s the best cornerback in the ACC?

We attempted to tackle this question at the midpoint of the season, but there were many big games left to be played, so the metrics have shifted a bit since then.

Our All-ACC team selected Florida State’s Jalen Ramsey and Clemson’s Mackensie Alexander, while Ramsey also nabbed a slot as an All-American along with Iowa’s Desmond King. But do those nominations stand up to closer scrutiny?

We dug into the numbers, using info from STATS, LLC that tracks targets for each defensive back.

The first question worth considering is obvious: Who covers the best?

The easiest way to measure this is completion percentage. A great corner won’t allow many passes to be completed, so the players with the lowest completion percentage certainly warrant discussion in this debate.

Using the numbers from STATS LLC, here are the ACC’s top 10 in terms of completions-per-target:

Alexander, Clemson - 31.0 percent

Marquez White, FSU - 32.1

Juston Burris, NCSU - 32.4

Brandon Facyson, Virginia Tech - 34.1

Cordrea Tankersley, Clemson - 35.6

Ramsey, FSU - 37.5

Isaac Yiadom, BC - 37.9

Breon Borders, Duke - 40.9

Lafayette Pitts, Pitt - 41.7

Darious Latimore, Virginia - 44.1

Alexander clearly states his case here, and Ramsey stacks up well, too. Of course, it also appears a few other corners warranted more consideration. After all, completion percentage isn’t the only measure of success. What about big plays?

If we look at yards-per-completion, our list shifts a bit. Tankersley leads the way, allowing fewer than 10 yards per catch. North Carolina’s M.J. Stewart, who also finished second in the ACC with 14 PBUs, is close with 10.44 per catch. Virginia’s Maurice Canady (11.93), Ramsey (11.95) and Wake Forest’s Brad Watson (11.98 with an ACC-best 18 PBUs) are also close. Alexander, at 18.9 yards-per-completion, was far more boom-or-bust.

On the other hand, those busts weren’t nearly as problematic as one might assume. Alexander was one of just six ACC defensive backs to face at least 40 targets and allow no more than one touchdown, along with Facyson, Pitts, UNC’s Des Lawrence, Miami’s Corn Elder and Virginia’s Demetrious Nicholson.

Lawrence is another interesting case. He was targeted 49 times and didn’t allow a touchdown. He also picked off two passes and broke up 14 more for a North Carolina secondary that was exceptional throughout most of 2015. He and Stewart transformed a unit that was awful last year into one of this season’s best.

But if those stats don’t make it clear who the best corners are, perhaps reputation should play a part. So we can also look at which corners were targeted least often this season.

Here we see a surprising tally for White, who despite working opposite an All-American, saw half as many targets -- just 7 percent of all throws against FSU’s defense went White’s way. Burris, Alexander and Lawrence show well here, too.

Still, there’s probably some extra context to consider. How good were the opposing passing games each corner faced? And how much havoc did their defensive fronts create? A quick look at some of our top candidates:

Overall, it looks like Clemson faced the best passing games, while Florida State and North Carolina got the least production from their defensive fronts (they finished 13th and 14th, respectively, in the ACC in pressure rate).

With all that in mind, let’s revisit our contenders.

White and Ramsey got relatively little from their defensive fronts, while both ranked well in completion percentage, and Ramsey was among the lowest yards-per-completion. White, meanwhile, was the most respected corner in the conference, in terms of targets.

Alexander and Tankersley both faced extremely good passing games, and no corner in the league allowed a lower percentage of completions than Alexander. Tankersley, on the other hand, allowed the fewest yards per completion.

Lawrence and Stewart both broke up 14 passes, both allowed relatively few big plays, and both had almost no help from their defensive front for a unit that had by far the biggest turnaround in 2015.

Facyson had a splendid year coming off injury, despite the loss of star Kendall Fuller on the opposite side. Burris, Watson, Elder, Yiadom and Pitts probably warrant discussion, too, but they’re not quite in that top tier.

Adding it all up, we’d probably go with White and Alexander as our All-ACC selections now, with Ramsey and Stewart as our second-teamers, and Tankersley and Lawrence on the third team.