Each sweeps period is heralded by a seemingly endless array of network specials designed to boost ratings. These specials may attain those big numbers – especially in the prized 18-34 and 18-49 demographics – but only at the expense of regular primetime programming.

In addition to high-profile competition between the networks – like CBS’ Classics weekend in February – another drain on series during sweeps is that independents also bring out their biggest guns.

The outlook for the May sweeps is that the drop will be even more precipitous (in May 1990, even a megahit like “Cheers” lost 1.4 million 18-34 viewers). But this decline is not unusual and is the most easily explained: In addition to the competition from specials, series are going into reruns, and increased daylight and warmer weather pull younger viewers away from the tube.

Series fare worse

In general, most weekly series fare worse in the 18-34 and 18-49 demos during sweeps months, with the exception of a few elite top 10 shows in the 18-34 age group. During the November ’90 sweeps, for example, NBC’s “Cheers” toasted 1.4 million more 18-34 viewers than it had in October, and ABC’s “America’s Funniest Home Videos” captured over 1.5 million additional 18-34′ s. (All figures provided by Nielsen Media Research.)

NBC’s “The Cos Show,” however, lost 400,000 female 18-34 viewers from October to November, ABC’s “Who’s The Boss?” dropped 850,000 total 18-34 viewers and CBS’ “The Flash” lost 900,000 of its 18-34′s (20% of its total).

While November reverses the May weather factor, and conceivably should add viewers to shows that lost out to the World Series, Larry Hyams, director of primetime analysis for ABC, says the decline is just part of a larger trend. “Most sampling of shows is done in September and October,” he says. “The numbers tend to drift downward slightly after that.”

The results were no different in the February ’91 sweeps. NBC’s “In The Heat Of The Night,” which has an older core audience (it scores especially well with 55-plus), fell from a 4.4 rating/12 share with 18-34 men in January to a 4.1/11 in February, and from a 5.5/13 to a 4.9/12 with women 18-34.

In addition, shows usually popular with 18-34′ s, like ABC’s “Growing Pains,” took an even sharper tumble. That show lost 18% of its men 18-34 and 17% of its women that age (dropping from a 9/24 to a 7.4/21 and a 12.7/30 to 10.6/27, respectively) from January to February.

Exceptions to the rule

There is at least one theory for every viewer lost. The Persian Gulf war, for example, has been cited as one reason for the numbers’ drop in the February sweeps. “It is like the English language,” says Bob Niles, NBC senior v.p., research. “There are basic rules, but there are so many exceptions to the basic rules that you have to take it on a case by case basis.”

The most notable exception is Fox, which showed increases in younger demos for almost all its programs from January to February. One example is “Parker Lewis Can’t Lose,” which climbed to a 5.4/14 from a 4.9/11 with men 18-34 and a 5.5/15 from a 5.1/12 with women 18-34.

And when Fox shows – which are geared more toward these young demos anyway – did not increase during February, they remained stable or declined more moderately than their counterparts on the Big Three nets.

B.J. Arnold, Fox’ director of sales research and marketing, says this can be seen as “a strong indication of viewer loyalty,” since Fox viewers are less likely to abandon the series for special programming. He adds that Fox helps this trend by bumping shows around less then the other networks.

Another contributing factor, says NBC’s Niles, is that Fox shows run mostly on independent stations, which bring out their best movies for sweeps month. Since these movies have improved demographics, promos for Fox shows are likely to be more effective. “What it all means [for Fox],” Niles says, “I’m not really sure.”

And even the Fox exception has exceptions – “The Simpsons,” which was in the top five for men and women 18-34 in last October’s sweeps, lost over 1.3 million 18-34′s during November.

“It is nice to win the sweeps period, but not totally relevant,” adds Niles. He says the networks have so much year-round information that sweeps figures do not make or break a show. “We are looking for trends over the course of time.”

The networks, in fact, say sweeps are really for the affiliates, who don’t receive the same wealth of Nielsen and Arbitron numbers year round as the nets. But several ad execs say most affiliates and sponsors are sophisticated enough to view the larger picture.

“The affiliates use the sweeps as a measuring stick,” says Paul Schulman, of Paul Schulman Associates. “Nine out of 10 clients won’t just buy the sweeps.”

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