TELEVISION network rivalry has taken on a new dimension: self-criticism.

This year, for the first time, the networks have hired reviewers to tell us what to watch -- and the tougher the critics are, the more their employers seem to like it. It's good for the system, they say. But it may also be good for profits.

NBC's "Today" started in all last Jan. 8. "The Lord knows bad programming is nothing new to television," critic Ron Hendren commented during his first week, "but the NBC special 'Charleston,' which will air tonight, may just be among the worst two hours of prime time we'll have a chance to see this year."

He was talking about a program presented by the people who sign his paycheck.

Twenty days later, CBS's "Sunday Morning" introduced critic Jeff Greenfield. He mocks television programmers, criticizes network management and lets loose deadly streams of invective such as "the mix of pseudo-celebrities and smarmy, naughty, giggly questions that make up programs like 'The Match Game.'"

Greenfield, too, insults the boss. "Last fall," he recently told viewers, "CBS's promotion for its new shows promised "Turn Us On, We'll Turn You On.' Obviously one demand of feminism has been heard here. For the second season, CBS boasts: 'We're Coming On.' Next fall, I believe, the slogan will be "Our Place or Yours.'"

On Sept. 7, ABC joined the fray. Rona Barrett of "Good Morning America" began a two-week series of two critiques each morning. One of her first reports said that the network's new "240-Robert" "isn't very good" and was "assembled right out of a catalogue made to order for the teenage hearthrob set." "Do yourself a favor," she told viewers, "turn your dial." Barrett then provided program listings for NBC and CBS. Even when she praised an ABC show, Barrett said its "script suffered from terminal predictability" and the program "could head for the morgue.

Suddenly, TV has turned on itself. Until this year, television studiously refused to discuss itself, forcing people to turn to newspaper and magazine coverage of the nation's dominant source of information and ideas. To get an idea of how revolutionary those "turn your dials" are, one need only remember that until recently talk-show hosts referred vaguely to their competitors as "another network," as though they existed on a faraway galaxy.

"This sort of thing just hasn't happened before, says Erik Barnouw, author of the definitive History of Broadcasting in the United States. "The last time I can think of such criticism on a national basis was the radio program 'CBS Views the Press' during the Edward R. Murrow era."

During the past quarter-century, about a dozen stations in major markets have experimented with locally produced programs examining television. Few lasted. The most notable exception ran on WFAA-TV in Dallas. It appeared just after the speech in which Newton Minow, John Kennedy's new FCC chairman, called television a "vast wasteland," and ran until last year. Television critics emerged in the early 1970s. One of the first was Hendren, brought to Washington audiences on NBC-owned-and-operated WRC in 1976 by Joe Bartelme, now executive producer of the "Today" show.

"We criticize everything else around us, so why shouldn't we criticize television," explains Bartelme.

Sam Zelman, who in 1977 hired a television critic at Washington's ABC affiliate, WJLA, said he simply concluded that "since television was a six-hour part of everyone's day," it should receive coverage.

"I'm not sure we as an industry have been broad-minded," says Squire Rushnell, ABC vice president of children's and early morning programming. "This criticism is the result of an evolution of attitudes."

Network executives make no excuses for their belated discovery that television is important enough to criticize. Indeed, many may not regard television as a newsworthy object, and the self-criticism boom may only reflect TV's consistent ability to produce programs that will attract the largest possible audiences. "People is this country are less interested in politics," explains one executive. "What sells is entertainment and stories about entertainers. People in television are now beginning to perceive this. "And what the critics are talking about, of course, is entertainment.

Historian Barnouw shares that cynicism: "One reason this is happening is that there's been such a barrage of complaints about television. One is that television itself is a problem never discussed on television." Barnouw maintains that by choosing program critics as the principal examiners of their own industry, networks have "selected for public discussion one of the least serious problems about the effects of television." Among those problems he cites are a television "world depicted so simplistically no one can understand what's going on," "the shunting aside of news in favor of a second reality," and "the creation of an electoral system in which access to the voting population is almost entirely via buying spots."

Barnouw doesn't believe the critics really can be independent. "It's an implausible thing," he says. "The person doing the criticism won't forget he's part of a particular network."

The critics disagree. "I don't consider myself a network employee," says Greenfield, a former speechwriter for Robert Kennedy and currently a magazine writer and author of numerous books, including "Television: The First 50 Years." "I'm a free-lance writer on contract basis. I don't get a blazer and I'm not on the health plan. I just have to show up with my clothes on."

Barrett, who has done television criticism, movie reviews and entertainment industry news during 14 years as ABC's Hollywood reporter, says that her "attitude has always been to inform the public about what's happening in the entertainment industry," and that "ABC says that Rona Barrett's salary is "not a matter of public record, but speculation in six figures would not be unreasonable."

NBC's Hendren, a free-lancer like Greenfield, says that "besides avoiding certain words, anything libelous and criticism of shows in competition with "Today,' I can do whatever I want." "Today,' show producers sometimes suggest changes, as when Hendren -- seeking an analogy to show how little talent some actresses have -- substituted "Bella Abzug's hatband" for a reference to "Goldie Hawn's cleavage" in order to "avoid offending the predominantly female audience." His scripts arrive in New York a day before broadcast, but by then the taping already is finished. "We don't talk to him that much," says executive producer Bartelme. "I've cringed at some of the things he's said, but that's been personal disagreement, not professional."

During his first week on "Today," Hendren shocked the broadcast industry not only by blasting NBC's "Charleston," but also by suggesting that viewers switch to CBS's "WKRP in Cincinnati."

"I didn't consciously set out to prove my independence," Hendren says. "I was previewing available shows. I saw it. It was awful. I said it was awful. I honestly expected no fuss to be made about it."

Hendren says he feels pressure only "from entertainers and their agents" whom he "simply ignores." "I had to establish, not independence, but a reputation for responsibility and reliability," he explains.

Hendren's suggesting that viewers switch stations angered at least one affiliate and prompted Dick Fisher, executive vice president at NBC News, to promise it would never happen again (third-place NBC has been losing important outlets to ABC and can't afford to ignore grumbling.) Fisher's edict never officially reached Hendren, and the censorship issue seemed to die.

This incident points out an important -- perhaps even essential -- aspect of the television-criticism phenomenon: The networks want their critics to be extra mean. They seem to enjoy the self-flagellation. And they certainly appreciate the attention.

"You should have seen Rona blast a new ABC show this morning," exudes an ABC spokesman. "She was really tough. She's not just a gossip columnist. She's really very talented."

Flagellation lets networks feel good about themselves and helps them convince the public that they are unbiased and statesmanlike. "We're maturing," says a CBS official. Adds "Today" show West Cost producer Scott Goldstein, "I'm by no means a company loyalist, but we've broken new ground. It's very startling, somewhat amazing and remarkable. It's a noble thing NBC is doing."

In the world of television, nobility need not cost anything. Ratings determine profits, and no matter how outspoken the critics may seem, they aren't likely to change the numbers.

One prime-time rating point equals about 1.5 million viewers. Nielsen figures show that Hendren reaches about 4.1 million, Barrett 3.9 million and Greenfield only 800,000.

To change even one rating point, Hendren would have to alter the viewing decisions of over one third of the entire "Today" audience and Greenfield would have to affect twice as many people as he actually reaches. Furthermore, there's no reason to believe any shifting occurs. "How you measure the effects of televised criticisms is beyond Nielsen," says a company spokesman. "Whether it would shift viewers would be just pure speculation."

"Today's" Bartelme "doubts that the reviewers affect ratings" and says no one at the network has tried to find out. "Newspaper reviews don't really affect ratings either," he adds.

Robert Karl Manoff, editor of the Columbia Journalism Review, believes that "although the critics do some things of value, the institutional context in which they operate" determines their effect. "Whatever they say is absorbed in the bureaucratic structures of the industry on the one hand, and in people's viewing habits on the other." Viewing, Manoff says, is "largely uncritical."

Television is a multibillion-dollar industry with millions riding on each rating point, and in the economic trenches -- at the affiliated stations -- critics don't seem to cause real concern.

"I've received no complaints from members," says WDSU-New Orleans General Manager Jim Yeager, Board Chairman of the NBC affiliates organization. "Those reviews are going to a relatively sophisticated audience and have no appreciable impact. A bad review may even titillate a little."

This last point may be revealing. Political and advertising professionals frequently say they don't care what's said about their candidate or product as long as the name is pronounced correctly. It's the attention that counts, and a bad review is preferable to no review at all. So when Jeff Greenfield criticizes CBS for using sexual suggestibility, the audience may carry away not negative impressions, but a warm feeling that CBS is somehow associated with sex. This kind of inadvertent advertising may actually serve to increase viewers for the network criticized.

After Hendren attacked "Charleston," one network executive told the New York Times that the review could increase the program's audience. (It received a respectable 30-percent share.)

"Theater critics have panned a number of shows, and yet they've been hits," points out Edward Pfieffer of Washington's WDVM, a former chairman of the CBS affiliates association.

"People will want to tune in just to see who we're zinging. They'll talk about it at the office," says one station manager. CJR's Manoff agrees: "This kind of criticism becomes another form of entertainment."

"I'd like to do it on our local news," comments another. "The only reason I don't is that I can't find a writer who can verbalize well on television."

Bartelme says that NBC President Fred Silverman, a man not known for his indifference to ratings and profits, "didn't hesitate 10 seconds" when the idea of a television critic was suggested. "We hired him on one basis," Silverman said recently, "that if we're going to have a critic, we're going to allow him to be a critic. If he doesn't like our shows, then he has every right to say it."

One indication that reviewers may exist only as long as they make economic sense -- and not because responsibility mandates them -- is their impermanence. Network programmers work in clusters. When one show featuring blacks is popular, a half dozen imitations appear. When Sonny and Cher got high ratings, other programs present caustic couples. Critics are now in vogue.

"After two or three years anything can get stale," says Bartelme. "You always have to try new things. I've knocked off political commentators, a financial expert and a psychologist because they didn't work. Television criticism has worked."

ABC's Rushnell says this aspect of Rona Barrett's tenure won't last past the introduction of the new television season. "We have to remember that Rona hasn't suddenly become a television critic," he explains. "She is our television reporter, and as part of a normal reporting process she will tell viewers about new series."

At CBS, Greenfield feels that "only time will tell" and that one reason he's "left alone is that it's Sunday morning." He points out, however, that CBS's "60 Minutes" has done "hard-hitting" exposes on ratings, religious programming, affiliate junkets and Norman Lear.

Notes NBC's Goldstein, "Fred Silverman could wake up tomorrow morning and say, 'You know something, "Supertrain" was canceled, and so is Ron Hendren.'"

Greenfield feels that the critics are more sincere, that exposure gives them job security. "Unless I drool or stutter, they can't clamp down on me without hurting their integrity," he says.

In the meantime, television criticism of television remains a phenomenon with a certain cachet. In early October, Hendren will join a movie star, a television starlet, a stand-up comedian and a fashion show as a guest on "Merv Griffin."