TELEVISION : Why the Stand-Up Routine Works : How many network execs does it take to make a hit sitcom? Just the one lucky enough to find the next Seinfeld or Roseanne. Stand-up comics are today’s hitmakers. But how does that differ from TV’s past?

When a forlorn young woman in Thomas Pynchon’s “Vineland” wished that life could be like a sitcom, with a wisecrack for every occasion and all of its problems wrapped up in 30 minutes--cut to final commercial--she didn’t know how accommodating the television industry would eventually be.

These days, anyone can take a Voyager-length trip through the empyrean reaches of sitcom syndication, with orbital laugh tracks beaming out from “I Love Lucy,” “Gilligan’s Island,” “Family Ties,” “Cheers” and “Empty Nest,” among numerous others, and never touch down in a world that isn’t swaddled in yuks (and we haven’t even veered into cable).

Dave and Jay will ease us out of catastrophic news reports and into the night with choice quips and the celebrity fix to show us that life can be beautiful for at least some of us.

The sitcom reorders the world altogether. A pretense of normality, someone’s zany entrance, a comic misunderstanding, a few jokes to ease everyone toward reconciliation--and calm is restored until the next episode.

Like the professionally embalmed, it’s incorruptible. It’s where everyone’s glad to see you and knows your name. The Huxtables will point a moral for you. Roseanne’s house may be locked in the humid anguish and cheap smells of a school cafeteria, and its continuing familial beefs may hang in the air like razor wire, but you’ll never be denied a place at the table.

Now, in the downsized ‘90s, the sitcom is taking a new turn. Where once comedic actors like Dick Van Dyke and longtime comedy pros like Bob Newhart headlined their own shows, now relatively unknown stand-up comedians are coming out of the clubs into prime time, bringing with them new adoptive families and friends and ‘90s attitudes of ironic diffidence and diminished expectations.

Look at the ratings. For the prime-time season that just ended, five of the six most popular shows were sitcoms that starred stand-up comics (“60 Minutes” was the lone exception). Tim Allen heads the No. 1-rated “Home Improvement” and Jerry Seinfeld is in the No. 3-rated “Seinfeld.” Roseanne Arnold in “Roseanne” finished fourth, followed by “These Friends of Mine,” which stars Ellen DeGeneres, and “Grace Under Fire,” featuring Brett Butler.

Network executives, part of whose survival depends on staying ahead of the curve, haven’t been waiting around to see if the trend is just a passing fad. This spring they ordered pilots starring Rita Rudner, Rick Duccommun, Jeff Wayne, Howie Mandel, Carlos Mencia, Lewis Black and Lisa Ann Walter, among others. And while none of those made the cut for fall, two others did, both at ABC: Steve Harvey will play a dad in “Me and the Boys” and Korean American Margaret Cho stars as a woman aspiring to be the “All American Girl.”

The fall lineup will also carry a number of familiar faces of comedic actors--including Dabney Coleman, Martin Short, Hal Linden and Suzanne Pleshette--but no one challenges the notion that the stand-up-to-sitcom transition is a fait accompli.

“The search for the good stand-up comedian to base a series on is ultimately about finding the next big hit,” says Sandy Grushow, president of the Fox Entertainment Group. “What the good ones bring is a distinctive point of view, like Martin Lawrence, who had something to say before he ever got to his sitcom (Fox’s “Martin”).”

Says NBC Entertainment President Warren Littlefield: “Comics stand in five-hour-a-night lineups all over the country. They have to earn their keep by being distinctive in some way. When television goes from 10 channels to 35, then 60, and with the upcoming information superhighway, 500, it’s to your advantage to bring in someone who’s already discovered how to be memorable.”

The formula for successfully shaping a show around a comic’s attitudes and persona is by no means guaranteed, as Richard Lewis and Don Rickles will tell you after “Daddy Dearest,” or Tom Arnold will tell you after two strikeouts--even as Roseanne Arnold gives new meaning to the phrase “significant other.” They were part of last season’s casualty list, which included fellow stand-ups Sinbad, Thea Vitale and John Mendoza.

But the successes have been spectacular, producing hundreds of millions of dollars in revenue for networks, producers and stars (Bill Cosby’s syndication deals for “The Cosby Show” alone earned him more money than the gross domestic product of some Third World countries).

“NBC didn’t think that highly of ‘Seinfeld’ at first and stuck it in a summer slot, figuring no one would watch it,” says David Steinberg, who as actor, writer, producer and director has touched all points of the TV comedy compass. “Now a number of execs are saying they knew it’d be a hit all along and have moved up into expensive homes.”

“I think we’re seeing the continuation of the cycle that began when so many stand-up comics surfaced through the ‘80s,” says Garry Shandling, star of HBO’s “The Larry Sanders Show.” “The peak of the stand-up era is over. The clubs are having a tough time economically. The comedians have to move on. Sitcoms are giving them an opportunity.”

The sitcom’s differing incarnations have been drawn from a surrounding cultural atmosphere. Early on, with players like Molly Berg and Burns & Allen, it was a nostalgic carry-over from radio days. “Father Knows Best” summed up the white, orderly middle-class 1950s, where Dad never took off his tie. “All in the Family” recorded the ‘60s tectonic grind between generations. Mary Tyler Moore exemplified the feminist assertion that a single working girl can do very well on her own, thank you. Bill Cosby rose with Ronald Reagan’s Morning in America sun . Roseanne and Dan Conner worked grimly through the long minimum - wage hours of the decade’s twilight.

What of prime-time stand-ups in the ‘90s? “Roseanne” still bares the fresh bruises of modern familial life and its confusions; its jokes are yelps of pain. “Home Improvement’s” light veneer of sophistication is based on a central character who’s flawed, like everyone else (though more impulsive about it), but is not a complete fool; there’s a basic level of good-natured tolerance at its core. But these shows don’t quite feel like the ‘90s, at least not like “Seinfeld” or “These Friends of Mine,” which has been retitled “Ellen” for the fall. (Butler of “Grace Under Fire” is soul sister to Roseanne.)

Do Seinfeld’s and DeGeneres’ comic instincts accurately clue us in to a widely shared experience that makes us a little less lonely in the dark surrounding the tube? Or do they signally bring us a narrow generational slice of characters with little in mind, peculiarly insular people to whom getting a table in a Chinese restaurant is a major issue and sleeping with a virtual stranger or dumping someone is no issue at all? And as performers, are they representative of our new Age of the Amateur, where no one needs traditional training and performance skills to get by? Whatever you want to say of newcomers Margaret Cho and Steve Harvey, they are not fine actors.

These are important concerns to some industry pros.

“There’s a plus and a negative to all this,” says writer-producer Matt Williams, who worked on “The Cosby Show,” was the creator of “Roseanne” and is the driving force behind “Home Improvement.”

“The plus is that, to fill that half-hour, you need people who understand comedy and comedy changes. Good comedians already bring their sense of timing, delivery, attitude. The negative is that, with rare exceptions, they’re not actors. So what often happens is that you get comic delivery instead of capable acting. A lot of shows have failed, not only for that reason, but because the stand-up hasn’t brought a point of view you can build a show around.

“Creating a successful sitcom is like building a basketball team,” Williams continued. “Even if you have a Michael Jordan, you need a team around him. The good sitcom team builds on the comedian’s persona and point of view. But he or she still has to be able to act, or to generate action. To stand and deliver observational material isn’t the same thing.”

Williams is concerned over the drift that some of the newer sitcoms are taking--that is, abandoning character in deference to attitude: “The best sitcoms have always been about human beings and what happens between them. Now it’s someone saying, ‘Huh?’ People are smugly detached, unwilling to care, to commit, to feel passionate about something. A lot of the half-hour shows have people who ignore consequences, as if to say, ‘I’m not responsible.’ The average household watches 50 hours of TV a week and considers what it sees acceptable behavior. Can you imagine Mary Tyler Moore saying, ‘I’ll just screw this guy on my first date?’ ” (This is in reference to the first-episode premise of “These Friends of Mine.”)

Writer-producer Robert Weide (“Mastergate” and the Emmy-winning “W.C. Fields Straight Up”) has mixed feelings about the sitcom’s new trend.

“For a sitcom series, you need good writing and the dynamic of an ensemble,” he says. “Jerry Seinfeld is an entertaining comic with a small vision. He’s not a good actor. But he’s likable. The show has all these interesting characters, and a lot of people of my generation (Weide is 34) relate to it because of their relationships and how they think--like how George and Jerry scheme to meet women. When it’s well-written, it holds you. When the writing stops, you notice it.”

As an expression of the emerging ‘90s sensibility, Weide concedes of the characters on “Seinfeld,” “their lives are kind of shabby. I’m embarrassed to relate to the show because of its small thinking. Whole episodes are dedicated to things like finding your car in a parking lot. ‘All in the Family’ dealt with issues. Now it’s about personal matters.”

David Steinberg cites another, less obvious factor that could be juicing the trend along, which relates as much to corporate politics as it does to the emergence of a new genre of artist.

“Nothing at all about being a comedian is amenable to being a comedy actor in a sitcom,” Steinberg says. “And there are some comic actors who are funnier than the comics themselves, like Robin Bartlett, who’s not a stand-up comic. Or Judith Ivey, who can’t not be funny. But it gets the pressure off the backs of the execs. If someone comes along who’s not a proven commodity, and fails, they can say, ‘Everyone says he’s so funny and it didn’t happen.’ It’s less damaging to them.

“Bill Cosby and Roseanne Arnold came up with monster successes that showed if you get the right combination, you can explode. The networks stand to make $200-400 million in revenues from shows like those.”

But that also creates pressure in the networks’ corporate hierarchies to look for the formula that can replicate those successes.

George Carlin of Fox’s “The George Carlin Show” considers the trend one of supply and demand.

“The greatest demand TV has had historically is for comedy shows,” Carlin says. “Now the supply of comedians has increased. Through the clubs and cable, a lot of people have risen to visibility. TV has seen them as another way to go. Most of the older sitcoms were based on premise. Now, more and more, you get the person and then develop the premise.”

Carlin doesn’t see the sitcom as a metaphor for community, unlike other critical observers, but he acknowledges that the better ones are not easy to do. “It’s commerce, pure and simple. It has nothing to do with art and little to do with entertainment. It’s just to sell biscuits. The important thing is that you keep control and you have a good team around you, or else you can get lost.”

Garry Shandling is also mindful of the deadly serious pressures that surround what for the viewer is mostly 22 minutes of laughter and escape. As a successful stand-up who began writing for “Sanford and Son” in 1976, and later for Gabe Kaplan and Danny Thomas, Shandling was in line for a show of his own, and at first resisted.

“In the early ‘80s, I was still exploring who I was comedically; I didn’t want to be forced into a mold that wasn’t me,” he says. “I didn’t want anything with kids and dogs. At one time I had a development deal with NBC. I had already been an experienced sitcom writer. The pressures to fit into a mold were enormous. That’s why I think shows like ‘Seinfeld’ and ‘Roseanne’ deserve enormous credit for holding on to their point of view.”

One of the ironies of the current trend is that, where television is apparently drawing more and more on the fresh blood of stand-up comedians, most of the comedians themselves, generationally speaking, have come from television--that is, the almighty wet nurse that Howard Beale railed against in “Network” when he charged to a studio audience, “You eat television, you dress television, you are television!”

But there may be a growing intuition within the creative end of the industry that the sitcom needs to step up to another level to stand out in a growing field of competition, and the best stand-ups, whose profession requires fearlessness as well as an alertness to social nuance, are helping shake it loose.

There will always be the use and maybe the necessity for the sitcom to continue as a kind of video Prozac, but if “NYPD Blue” and “Prime Suspect” can bring a darker, subway-rumbling vibration to the cop genre, the re-conceived sitcom can refresh our sense of community by allowing some of the acrid fumes and anxious sweats of the real world into a tradition of spotless interiors. “Roseanne” showed a beginning, and Brett Butler’s low-frequency surliness is a continuing rebuke to the relentless forces out there that grind a single working mother down.

Too, the fallout from the ‘80s comedy boom has sifted through the culture, pollinating it with jokes. The front sections of news magazines now look like visual equivalents of late-night monologues. Right now, the sensibility coming out of the new sitcoms is a mixed bag. Part of it is the junk-food product of a smug generation characterized by Garrison Keillor as being “all nostalgia and no history,” of shared ironic attitudes with no known possession of worldly knowledge. But part of it is closer to the bone, to an everyday American reality that the better comics bring in from a life on the road, the disappearing world beyond television.