Last week, the latest numbers for Modern Family‘s freshman run in syndication came out. The Emmy winning ABC comedy, which airs on USA and in broadcast syndication, hit new combined highs in all key measures, including households (5.1), Adults 18-34 (3.1) and Adults 18-49 (3.1). Modern Family now ranks as the No.2 program in all of syndication among 18-49 behind The Big Bang Theory (3.4) and is No.1 in 18-34. At the same time, the season to date rankings for all broadcast programs came out, and Modern Family is averaging 5.0 in 18-49 in 18-49 through the first 12 weeks of the season (in most current ratings that include DVR playback). That is not bad, as Modern Family is tied with NBC’s The Blacklist for No.3 in 18-49 behind Sunday Night Football (7.9) and Big Bang (6.8). But vs. the same 12 weeks last season, Modern Family is down 21%. That despite the show’s solid start in syndication.

It takes time for shows to take hold in syndication, and rarely someone breaks out right out of the gate no matter how big the rollout promotion. Big Bang too gradually grew into the monster ratings generator it has been for TBS. But by this point, the shows usually hit their stride (Modern Family, for instance, is up 15% from its premiere week in syndication among 18-49 and up 29% in 18-34) and the impact on the show’s broadcast run is felt. Through the first 12 weeks of fall 2011 when Big Bang launched in syndication, the show had shot up 21% season vs. season on CBS. Compare that to the 20% drop for Modern Family. The discrepancy is pretty staggering, given that both comedies had successful launches in syndication supported by massive marketing campaigns.

Industry insiders seem puzzled and no one can offer a reasonable explanation. Among the suggested possible reasons is the overall softness of ABC’s lineup this season but that hasn’t stopped a show like Scandal from excelling and posting year-to-year gains. Some point to the fact that ABC doesn’t have football to use as a promotional platform in reaching a broader audience the way CBS has at its disposal for Big Bang. But then, Fox and NBC too have a lot of NFL coverage and that hasn’t helped much their live-action comedies, most of which have been middling at best this fall. Then there is the show itself. Modern Family finished last season down 11% from 2011-12. Coincidentally, Big Bang too took a dip in the season before its launch in syndication when it moved to a new night, Thursday, and away from the protection of a Two And A Half Men lead-in. But it’s probably not a coincidence that that same 2010-11 season, Big Bang expanded its cast with the addition of Mayim Bialik and Melissa Rauch. The series found another gear creatively with the new dynamic of seven main characters and has been on a ratings tear ever since, growing each season. Meanwhile, Modern Family, while still solid and a reigning three time best comedy series Emmy winner, has lost some of the creative sizzle of its early going. (The ABC comedy remains the most upscale series on TV, edging Big Bang as the No. 1 show among Adults 18-49 in homes with $100k+ annual income, 8.6 vs. 8.4).

There is still time to turn things around as syndication ratings tend to peak early in the calendar year, often in February, so we may see some improvement for Modern Family when it returns in originals in January (It finished its fall run on a higher note). Big Bang hit series highs in the 2013 portion of last season, along with CBS drama NCIS, another series whose broadcast ratings had been boosted by its off-network run.