Those slippery movie ratings, from the friendly G to the dreaded X, will be 14 years old Nov. 1.
Are they useful? Are they working? Are moviegoers - and their children - better off with them than without them?
The rating board and its parent organization, the Motion Picture Association of America, claim the rating system is demonstrably helping ''those whom it is designed to serve - parents of America.'' According to the MPAA, independent surveys find three out of five parents giving a ''favorable verdict'' to the ratings as currently administered.
Yet questions persist among moviegoers, parents, and observers of the motion-picture industry.
* A reporter in New York City visits theaters on a Saturday afternoon, and finds flocks of unaccompanied youngsters at such R-rated films as ''Cat People'' and ''Richard Pryor Live on the Sunset Strip.'' Officially, R means no one under 17 can be admitted without an adult.
* Parents in Michigan file suit against a theater that refused to admit their children to the R-rated ''Animal House.'' Two lower courts and the Michigan Supreme Court reject the contention that the civil rights of these youngsters, ages five through 12, were violated.
* A local rating group in Dallas decides the PG rating of ''Poltergeist'' isn't strong enough. City attorneys bring suit against the film's distributor, claiming it should be advertised as ''unsuitable for children.'' A jury finds otherwise, upholding the PG tag and its mild warning of ''parental guidance suggested.''
Emotions run high over movie ratings. While some parents applaud the system for keeping children out of objectionable films, others fault it for being rigid or arbitrary.
Meanwhile, debates rage within the movie industry itself. Many professionals welcome the rating system, claiming it holds outside censorship at bay, while providing useful information to wary ticket buyers. But some regard the system as a form of disguised censorship. They note that producers often feel compelled to reedit their films in order to avoid ratings that might be harmful at the box office.
The R rating has come under especially strong attack from some critics, who claim it has become a perverse advertising tool - symbolizing lurid or sensational content, yet not hindering young customers in big-city areas where enforcement of the ''restricted'' category by theater owners may be lax. Rating-board chairman Richard D. Heffner has suggested that as many as 85 percent of American theaters adhere to the rating system. Still, enforcement of the R tag is seen to vary from place to place.
Through all the debate over fairness and effectiveness, the recurring motif is the difficulty of cramming the world of cinema into a handful of loosely defined pigeonholes. In deciding how to tag a film, the Classification and Rating Administration considers only four criteria: theme, language, violence, and nudity and sex.
The one hard-and-fast requirement is an ''automatic language rule'' that mandates an R rating for any film containing ''one of the harsher, sexually derived words.'' Aside from this regulation, each rating represents the board's spontaneous judgment on the individual picture brought before it.
The rating board prides itself on being flexible, and taking every movie on its own merits. This may help to deflect some of the more generalized criticisms faced by the board. But it does little to answer the basic philosophical questions of what constitutes ''good taste'' and how much is ''too much.'' As the MPAA asks in its literature, do marines storming the beach at Iwo Jima represent ''too much violence?'' Is a showdown between a sheriff and a rustler too violent, ''or does it require the spilling of blood to draw a more severe rating?'' Where is the dividing line between ''all right'' and ''too much'' in a screen fistfight?
Moreover, times change. Films rated in the first years of the system were judged differently, in some respects, than are current movies. It is hard to imagine the X-rated ''Midnight Cowboy,'' for example, receiving anything more harsh than an R by today's standards. Rating-board chairman Heffner grants that the system used to be harder on nudity and sexuality, and softer on violence, than it is now. He defends these stances as appropriate to current parental attitudes. Yet parents who feel recent ratings are too permissive may think stricter standards are always appropriate, and deplore the idea of shifting according to current fashion.
Simplifying matters for the rating board, but often misunderstood by its critics, is the board's refusal to approve or disapprove of any film. ''We are not moralists or critics,'' says rating-board chief Heffner in a TV Guide article. ''We are not censors. Nothing we do affects the moviegoing of anyone other than these young people. . . .''
Still, parents often expect more of the rating system, and some cities have tried to do something about it. Chicago's police department has maintained a rating board for more than 50 years, with five civilians tagging films X or ''non-X'' to show suitability for persons under 18. Dallas's board, appointed by the City Council, hands out ratings similar to the nationally known G and R - adding code letters, in some cases, to show whether vulgar language, violence, or sex are present. Similar boards in Milwaukee and Detroit check films for obscenity.
At times, such local groups come into direct conflict with the MPAA rating board. Such was the case in Dallas, after the distributor of ''Poltergeist'' - the Metro-Goldwyn-Mayer/United Artists Entertainment Company - refused to display the local board's ''not suitable'' rating in advertising and at theaters. The city sued MGM/UA, but lost when a jury decided the film's violence was not ''patently offensive'' and that the MPAA's PG rating was sufficient.
Even the MPAA itself had its hands full with ''Poltergeist,'' however. Reportedly, the film originally received an R rating which was then changed to PG by the appeals board, which reconsiders ratings that have been contested by filmmakers. Since decisions by the appeals board are final, PG became the official rating for ''Poltergeist,'' which went on to wide popularity among young audiences. As with all its cases, the appeals board refuses to comment on or discuss the matter.
On average, about a dozen ratings each year are challenged and brought to a vote by the 26 members of the appeals board, who represent three film-industry groups. Original ratings are reversed in some 43 percent of these cases, most of them involving the ''automatic language rule.'' While the rating board is bound to bestow an R in all cases where certain language is heard, the appeals board is empowered to ''soften'' the rating (making it PG instead) in cases where tone or context are considered to be mitigating factors.
Thus even the presence or absence of vulgar language is treated flexibly by the MPAA rating process as a whole. Some observers welcome this flexibility. Others have expressed consternation that a ''Nashville'' or ''Harry and Tonto'' are rated R for one-time use of vulgarities, while such pictures as ''All the President's Men'' and ''A Bridge Too Far'' are tagged PG.
The case of ''President's Men'' in 1976 raised a particular furor when some critics suggested the ''language rule'' was being overlooked because of the film's political stance, and warned that the PG decision would stand as a precedent making the ''language R'' harder to uphold in the future. MPAA chief Jack Valenti told this newspaper that the film's nonviolent, nonsexual context was the deciding factor, however, while Heffner maintained no precedent was being set. In the years since, numerous ''language R'' tags have been overturned by the appeals board, but the automatic-R rule has remained in place with the rating board and is frequently invoked.
Further complicating the rating situation is the ability of filmmakers to reedit their movies after release, in order to receive new classifications. ''A Clockwork Orange'' and ''Saturday Night Fever'' are two films that were initially released with strict ratings, then had new lives with milder ratings after a few offending details had been clipped out.
How are the four standard ratings holding up after almost a decade and a half? Some are proving more sturdy than others.
* The G rating - ''suitable for general audiences'' - has waned almost to the vanishing point. Only seven films received the G tag in 1981, down from 16 the year before. Studios and distributors fear the G rating signals ''blandness'' or ''kiddie fare'' to audiences, and some filmmakers have allegedly added four-letter words or other vulgarities in order to avoid a straight G label. This is ironic, since some highly artistic films, including ''2001: A Space Odyssey'' and ''The Black Stallion,'' have carried G ratings.
* The PG category - ''parental guidance suggested'' - remains useful, though it is also shrinking. PG tags went to 104 movies last year, down from 145 in 1979. PG is the most disputed category, requiring the most delicate judgment calls from the rating board, as the controversy over ''Poltergeist'' demonstrates.
* The R category - ''restricted,'' with youths under 17 barred unless accompanied by an adult - has grown, reflecting continued sexual frankness and explicit violence in Hollywood products and foreign imports. R ratings went to 198 pictures in 1981, up from 155 the year before.
* The X - no admission to patrons under 17 - remains an unpopular category, shunned by most responsible filmmakers. Only 27 X ratings were given out last year, down from 30 in 1980. Though some major works by respectable directors have carried X tags in the past, including ''A Clockwork Orange'' and ''Last Tango in Paris,'' it is widely regarded as a sign of pornographic or otherwise dubious content.
Though MPAA president Valenti has long resisted tinkering with the rating system, certain reforms are known to have support both within and outside of the rating establishment. Many observers favor a fifth rating that would fall between PG and R, indicating that a film may be too strong for preteens but all right for those over 13 or 14 years old. Others have pressed for some coded indication as to why a film has been rated R - for one vulgar word, or for whole scenes of lewd and aggressive behavior.
And the problem of enforcement remains a bugaboo. No matter how apt or necessary a rating may be, it loses its meaning when theater owners ignore it, allowing unaccompanied youngsters into R attractions or failing to police ticket sales when X-rated pictures are on view.
Though many makers of R-rated films would like to see easier access by young viewers, not all critics of the rating system are apologists for rough or raunchy movies. Hollywood producer Robert B. Radnitz has long opposed the ratings on practical and philosophical grounds, though his career has centered around such family-oriented pictures as ''Sounder'' and ''Dog of Flanders.'' Even the traditionally conservative Walt Disney Productions has largely abandoned the G category, jumping into PG territory with the cartoonlike violence of ''The Black Hole'' and ''Tron,'' and the realistic depiction of teen-age life in ''Tex.''
''We are messengers,'' said rating-board chairman Heffner in a 1977 statement before a House of Representatives subcommittee. ''We only reflect what's in the films brought to us,'' he continued, adding, ''We can't do more.''
That isn't enough for parents and other concerned moviegoers who would like to see more restraint exercised - and perhaps enforced - in the influential movie world.