This isn't necessarily ratings related, but multi-cam versus single-camera sitcomes comes up in our comments discussions quite a bit. And there is actually a numbers component to it, mainly that multi-cam is cheaper.
The LA Times has a long story featuring what's going on with sitcom development at each of the broadcast networks (and in the case of The CW, what isn't going on with sitcom development since it isn't developing any). Fans of sitcom development and the multi vs. single cam debate should definitely check the full article out.
Of 71 scripted pilots in contention for slots at the five networks, 33 are half-hour comedies and 19 of those are multi-camera formats -- shows taped before a live audience, and sometimes enhanced by laugh tracks. Today, only CBS airs multi-cam sitcoms.
The multi-cam sitcom, such as legendary hits "I Love Lucy" and "Cheers," was once the dominant format in which to televise comedies, as much for conveying a theater-like intimacy to home audiences as for its relatively cheap production costs. But within the last decade, multi-cam sitcoms began to disappear, while single-camera comedies like "30 Rock" and "The Office," with its movie-like freedom, started to rise in prominence.
"The industry had been moving away from multi-cameras out of a sense that other formats offer more creative freedom," said Jamie Erlicht, president of programming at Sony Pictures Television. "But there's room for both and there's a real appetite in these economic times for the tried and true multi-camera format."
"Multi-cameras are cheaper," said Zack Van Amburg, president of programming at Sony Pictures Television. "But I promise you this: While everyone is being saner and smarter and the economics are more pressured than they ever have been, it's still a hit-driven business. I don't think if they didn't believe and we didn't believe that good multi-cameras can still break out that you'd be seeing this trend."
There's no doubt cutting costs is a paramount consideration this season. Cash-strapped networks have taken a number of steps to lower their expenses, including filming outside of Los Angeles to take advantage of tax incentives, reducing license fees, or asking talent to accept lower fees.