The Falcons almost certainly aren’t going to make the playoffs in Dan Quinn’s first year as head coach. That will be a letdown considering the historical record of 5-0 teams going on to the postseason but, honestly, if the Falcons finish 8-8 can anyone really say that’s far off from preseason expectations?

The sting of the collapse shouldn’t obscure the fact that the Falcons have well exceeded expectations in the area in which Quinn has the most expertise and input. The Falcons had the worst defense in the NFL in 2014, and now they have an OK defense.

That’s no reason for celebration but it’s significant under the circumstances. It’s also reason to believe ex-Seahawks coordinator Quinn can eventually develop a good Falcons defense with another offseason to make it his own.

To quantify the defensive improvement in Year 1 of Quinn I turn to the Defense-adjusted Value Over Average metric developed by Football Outsiders. DVOA includes every single play and measures success based on situation (such as down and distance and field position) and strength of opponent. Every NFL team uses some form of DVOA for self-evaluation.

Sterling Xie of Football Outsiders examined the first-year impact of new head coaches from 1999 to 2014 with clearly offensive or defensive backgrounds. He found that the defensive DVOA of first-year “defensive” head coaches improved by an average of just 1.4 percent.

Through 13 games the Falcons had improved their defensive DVOA by 8.3 percent, rising from 32nd in the NFL to 25th. Football Outsiders won’t update its rankings until Tuesday but the Falcons’ standing should improve after they handled Jacksonville’s pretty good offense on Sunday.

The Falcons clearly are a better defensive team under Quinn. It’s impossible to determine exactly how much of that is because of him because when a team changes coaches (or even when they don’t) lots of factors vary from season-to-season. Also, it’s easier to go from awful to a little bit better than from good to great.

But history shows Falcons have gotten much better on defense than is typical for a defensive guru in his first year as head coach. I’m inclined to think Quinn and top defensive aide Richard Smith have much to do with that. Remember that the Falcons are built to score points, with the offense helping the defense, and yet the opposite has been true more often than not this season.

The Falcons have managed this without a significant injection of defensive talent. First-year linebackers Justin Durant, O’Brien Schofield and Brooks Reed were risk/reward free agent signings. First-round pick Vic Beasley has been solid but the Falcons need a lot more help to fashion an effective pass rush.

Other than those players, it’s pretty much the same cast on defense in 2015 as it was in 2014. Also, two key holdovers have clearly declined: oft-injured and tackling-challenged safety William Moore, and third-year cornerback Robert Alford.

After Quinn guided a dominant defense filled with Pro Bowl talent in Seattle, he’s managed to build a respectable defense from a modest pool of talent with the Falcons. Contrast that to the offense, which gets most of the resources and has dipped from 10th in DVOA last season to 24th through 13 games this year. The salaries for quarterback Matt Ryan and wide receivers Julio Jones and Roddy White alone eat up about 27 percent of the team’s cap space.

The major marks against Quinn’s defense are that Jameis Winston 3rd-and-19 play and the first-half debacle at Carolina. But I think the solid effort at Jacksonville proves those are anomalies, and so does the performance of the defense in pretty much every other game this season. The Falcons are clearly better on defense and I think Quinn deserves much credit for that.

It won’t be enough to make the playoffs but it’s still important. It also should only get better: that Football Outsiders study showed that teams with “defensive” head coaches tend to improve on that side of the ball even more in Year 2 than in Year 1, and a bit more still in Year 3. Maybe by then Quinn will have an effective offense to go along with his improving defense.