STBeer is a product that Harry Wayne McMahan watches closely, and "beer is a tough one." He's full of admiration for Budweiser, but he thinks Schlitz is the pits.

The value pf McMahan's opinion has nothing to do with his taste in beverages - it's his taste in television advertisements that keeps paying audiences of ad men coming to hear his annual "100 Best" selections.

"McMahan, an advertising consultant with a library of 20,000 TV commercials in the library of his Escondido, Calif., avocado ranch, has a simple standard, as he told an audience here. "Commercials are the one form of communication that has a very accurate test of whether it's working" - the sales of the product.

He doesn't hide his scorn for people - even advertising people - who praise only the novelty or humor of a campaign, and mock something like "Ring around the collar." His 100 "most significant" ads are picked on the cash register, not the applause meter, he says.

The cash register test makes Budweiser's campaign a winner, he says, and a premier example of a successful commercial relying heavily on a jingle. The Clydesdales, the antique label emblazoned on parachutes, swimming pools and roofs, all do their part, but the jingle is fundamental to Budweiser's advertising success, he believes.

The Schlitz commercials, however, have been a resounding failure. They have consciously or unconsciously struck a homosexual theme, McMahan says.

Budweiser has now built a large lead nationwide and Miller, whose commercial McMahan likes, has moved past Schlitz second place, he says.

(At Schlitz headquarters in Milwaukee, a vice president for marketing confirmed that Miller has overtaken his company's beer in sales. As for the meaning of the campaign, he said: "Gusto describes in a very positive way taste attributes and a lifestyle that has been recieved very favorable by the vast majority of the consuming public."

Longevity is another McMahan touchstone. He notes that "Father Time," John Cameron Swayze, has sold watches for 22 years. Palmolive dishwashing liquid has used in Jan Miner as "Madge the Manicurist" for 12 years and Kellogg's Tony the Tiger has been growling about cereal for 22 years.

He advocates cutting out this stupid business of (frequently) changing campaigns.

"A few knocked Joe DiMaggio McMahan says of the Yankee Clipper's efforts on behalf of Mr. Coffee. He was dropped as the company's pitchmen, but he's come back, on McMahan 's words, "stronger than ever."

Sometimes, however, a celebrity and a product don't jibe. "John Wayne was something of a bomb in the headache field." McMahan says, but the Duke has gone on to a California savings bank where "he's at his best."

When McMahan is ased to name the best commercial campaigns of the 1970's, he cites Leggs and Winchester's small cigars.

In the early 1970s, there were 600 brands of hosiery and none had more than 4 percent of the market, McMahan says. After a couple of years of pushing its Leggs in their eggs, Leggs had a 30 percent market share, McMahan says with a touch of awe.

Winchester's success became a double-edged sword. When the Congress banned cigarette advertising from the airwaves Jan 1, 1971, tobacco-state legislators and others allowed small cigars continued access to living rooms.

In less than a year, small cigar sales tripled and R. J., Reynolds' Winchesters had 70 percent of the market, McMahan recalls. The only problem was their advertising became so visible that it came to the attention of Congress that there was a large loophole in its anti-smoking legislation, and small cigars were banished from television.

But many commercials on the air today are just registering through all the competition," McMahan remarks with regret.

He would like more sucess stories like those of Vlasic pickles, Vasine and Oil of Olay.

Vlasik now outsells Heinz pickles by 2 1/2 to one.McMahan reports, with its cartoon stork. Commericals asking "what time is Visine time?" have helped its sales leap ahead of murine, and Oil of Olay had gone from $6.5 million sales to $50 million after an extensive advertising campaign in a competitive field.

McMahan divides his winners into categories, including the 41 that use jingles; those that use new production techniques; those that employ a celebrity to pitch the product those using animation, and those he labels "product as hero."

Product-as-hero ads keep the camera on the product as it bubbles, cooks, cleans or whatever. One of McMahan's favourites is Pine-Sol, a house hold cleanner that outsells all its rivals and keeps commercials focussed on its seemingly undranatic bottle.

McMahan reminds his audience that product-as-hero commercials can be inexpensive - no celebrities to pay and no special sets.

Watching 100 commercials with no interruptions except for McMahan's brief commentary takes about 2 1/2 hours and leaves ones head jammed with the catchy tunes and sincere narrators voices.

The only big laugh at the presentation here was for American Tourister's commercial for its Verylite luggage. One after another, people approach a mud puddle at a curb. Some jump over it, sucked into an apparently bottomless puddle. Until, that is, a man carrying the company's light suitcase walks across the puddle without even wetting the uppers of his shoes. The suitcase is very light, the narrator stresses.

McMahan maintains that this year's "100 best" are superior to any other year's since television advertising began 30 years ago, he sees some ominous signs on the horizon.

Hes' not at all pleased by the advent of video games, which people hook to their television sets and play without commercial interruption.Nor does he look with favor upon public television or the coming of video discs.

It is ominous to McMahan that Americans in increasing numbers will be using their television set for such entertainment that will have no room for commercials and he foresees fractionally smaller total audiences watching regular commercial programming.

McMahan believes this will force creators of commercials to "win a more efficient, more incisive return" from these audiences and he's confident they can do it. "Look back at the first 30 years of commercial TV. We came a long way, Bobby," McMahan says.

In fact, McMahan believes that commercials have a lot to teach Americans if American would learn from them.

Half the populatio is under 30, McMahan notes and "most of them watched television before they learned to read and write."

These young Americans are "much more inclined to the visual than dependent on words; more emotional than logical," he said.

Rather than attempt to change that, McMahan suggests that educators adapt by borrowing the techniques of commercials. He urges the preparation of one or two-minute "briefing capsules" that a teacher would pop into a television set to give a class "the basic facts of the day."

"Commercials communicate in a certain style," McMahan said, "and the day you begin to use that is the day you bring your schools into the last half of the 20th century." The "briefing capsules" in McMahan's vision would be repeated frequently since, as advertisers have learned about commericals "you better repeat the damn things."

McMahan says Sesame Street "is doing a great deal of damage. Sure they learn their ABCs and their 123s, but when they get to school is the teacher doesn't get up there and act like Big Bird, they can't learn another thing."

The advertising industry treats McMahan with respect, but account executives don't live or die over whether they make his "100 best," which is printed in the trade magazine Advertising Age for which he write a column.

"It's a nice thing to be able to tell a client our campaign is one on the 100 best.'" one executive said, "it serves a purpose." He added that he'snever heard of a client switching advertisement agencies simply because of the McMahan ratings.