One weird stat that shows how good the Seahawks were in 2015

Now that the countdown of exhibition games has ticked to zero and the Seattle Seahawks roster been pared to 53, it’s time at last to fix our gaze upon the 2016 season proper. For all teams, before the football starts for real Thursday, it’s a time of boundless confidence—or at least confidential hope: In SB Nation’s NFL preview last week, 16 of the 32 editors surveyed saw their team winning at least 10 games this year. No fewer than six of those predicted as many as 12 wins, while another seven site managers were modest enough to say 10 exactly. If this preview came true, an incredible nine NFL teams with winning records would miss the playoffs in 2016, while only seven go worse than 8-8.

Of course this result is mathematically invalid; the predictions were not made holistically and they combine for way more than the 256 wins the league schedule allows. And though it is understandable to be influenced by hope and team-issued enthusiasm (we here are fans as well as analysts, after all—but then the same hobgoblin is a regular feature of ESPN’s NFL Nation bloggers’ previews too) these inflated numbers remind us to be guarded against the preseason optimism that springs so freely in September.

So it raises the question, are we overrating the Seahawks? Maybe. There’s plenty we don’t know. The squad, for example, now includes 14 rookies. That’s more than a quarter of the team, which seems like a crazy intrusion of new variables onto a depth chart that previously appeared so talented.

On the other hand, the starters are more certain. 19 of 22 first stringers were members of the roster at the end of 2015. One of the projected other three, Tony McDaniel (unless injured rookie Jarran Reed recovers quickly enough to become a week 1 starter), was also already on Seattle for both recent Super Bowl seasons, before spending last year in Tampa.

I can’t prove how well Seattle is going to do in 2016. The past doesn’t guarantee future performance, otherwise football would be boring. But I do think, after the hubbub of the draft and thirst of training camp and preseason excitement around the bright new faces—or even disappointment about prospects left behind—it’s worth reminding ourselves how good the Seahawks were already, before the offseason.

Here’s a funny comparison I came across while looking at Seattle’s figures from last year:

At first glance it’s not much of a comparison. It looks like one quarterback who is very good, and another who is pretty plainly terrible. But the strange thing is they have the exact same number of completions: 333.

These stats aren’t quarterback comparisons either, not directly; they are the Seahawks’ team passing totals (mostly Russell Wilson, but including six attempts and a sack of Tarvaris Jackson) and the composite data of all passers who played against them in 2015. So Seattle was excellent at defending the pass (no surprise) and also excellent at throwing the ball on offense (not a surprise unless you haven’t been paying attention—the Seahawks ranked second in passing DVOA).

The synchronicity in the completions column isn’t meaningful in itself. It’s a weird anomaly but it’s happened 20 other times in NFL history, to poor teams as well as successful ones. It happens whether a team throws the ball a lot, like the 2014 Denver Broncos, or doesn’t throw very often, like the 1982 Philadelphia Eagles. The number 333 also has no particular significance. The fact that it’s the same shows just how little value that volume has, out of context. But because it is the same, the coincidence is notable for how it helps put into clearer relief, without even any fancy math, how much better Seattle played than its competition.

While the Seahawks generated the same amount of completions as their opponents, they were far more efficient in doing so on nearly 60 fewer attempts. And while they generated the same amount of completions they were also more efficient with each catch, compiling 12 percent more passing yards than their opponents. The Seahawks scored almost two and half times as many passing touchdowns with those completions. (This is not an artifact either of the other teams happening to score more on the ground. Seattle gave up the same number of rushing touchdowns as it scored: 10.) Against the same amount of completions, the Seahawks produced only about half as many interceptions. And look at the differences between interception percentage and touchdown percentage.

Successfully completing passes is important in the NFL, no doubt. Russell Wilson together with the Seattle defense in 2015 displayed how much more important is the depth and breadth of what you do with those passes. Wilson led the league in passer rating last year, but though opponents were able to keep pace with the number of completions their combined rating would have placed them 30th. Critics point out that the Seahawks played a slew of backup quarterbacks to help the defense to that mark, but the disparity when overlaid against the identical completion total is still extreme.

Of course there’s more to the game than passing too, but even that’s highlighted in these figures: Seattle was able to be more selective with its passing thanks in part to its successful running and because the sturdy defense so often kept the Seahawks from falling behind. Again, this isn’t some secret, and there are plenty of other metrics that show even more comprehensively how Seattle was good at football in 2015 and that they’re likely to be good again this fall.

It’s just one dumb stat, but in a season of hope that will quickly provide whole new heaps of data to devour it’s just one more scrap to feed excitement until Sunday.