As Letterman Trails Leno, Will More Promos Help?

David Letterman’s new contract with CBS requires the network to throw extra promotional weight behind his late-night program, bowing to Letterman’s hope that will help narrow the gap between his show and ratings leader “The Tonight Show With Jay Leno.”

Yet after a tumultuous 10 days in which Letterman’s possible defection to ABC commanded national headlines, late-night ratings this week have been virtually unchanged, with Leno beating “Late Show With David Letterman” all three nights for which ratings are available--including Monday, when Letterman returned from a weeklong vacation and announced on the air his intent to stay at CBS.

Analyzing data from 50 major cities monitored by ratings service Nielsen Media Research that account for well over half of U.S. households (national estimates for late night won’t be available until next week), Leno has averaged a 4.6 rating and 12 share this week, meaning 4.6% of all homes and 12% of TV sets in use during that hour were tuned to “The Tonight Show.”

Letterman enjoyed a minor spike Monday, with a 3.9 rating and 10 share, but dropped the next two nights and averaged a 3.6 rating Monday through Wednesday, mirroring his average this season.

Meanwhile, “Nightline” averaged a 4 rating in its half-hour and “Politically Incorrect With Bill Maher” averaged a 2.7 rating, both deviating only slightly from their season-long averages.

Those results reinforce the sense that shifts in late-night viewing habits tend to be glacial, raising questions about how much impact additional promotion is likely to have--especially as long as NBC continues to beat CBS from 10:30 to 11 p.m., leading into late local newscasts. On Wednesday, for example, a rerun of NBC’s “Law & Order” more than doubled viewing of “60 Minutes II” in that half-hour.

The value of promotion may also be mitigated by how long the late-night players have been in place, with many people having made their viewing choices.

For the season, Leno is averaging 6 million viewers per night nationally, compared with 4.3 million watching Letterman.

Tune-in for both shows drops after midnight, and each leads ABC’s combination of “Nightline” and “Politically Incorrect With Bill Maher,” which would have been displaced had ABC landed Letterman. Those shows average 4.6 million and 2.6 million viewers, respectively.

Letterman’s contract calls for CBS to leverage assets from parent company Viacom to promote the show, including MTV, VH1 and more than 180 radio stations across the United States. Viewers can also expect to see extensive “Late Show” promotion during CBS’ coverage of the NCAA basketball tournament.