A ‘Five-Star’ Rating May Rely on Two-Cent Opinions : Lodging: Some organizations appraise hotels in a useful way. Other ‘shorthand’ ratings may mean little or nothing.

A luxurious hotel in Mazatlan , thought Barbara Meade Dedios. Great . She and her fiance, veteran travelers in Mexico, were planning their honeymoon in that area, and a travel agent with a package-tour company had found them a recently renovated “five-star” lodging.

They went. But instead of luxury, she reports, they landed in a “nightmare,” hounded by time-share-hawkers in the lobby, denied the view room they were promised and confronted by a dimly lit, purple-hued bathroom with problematic shower drainage. The pool area was poorly maintained, Meade Dedios adds, and she thinks the desk staff twice tried to cheat her in cashing her travelers’ checks.

Not, in short, a five-star experience.

Their story holds a lesson for all travelers: If you’re relying on a star-rating or any other shorthand assessment of quality in choosing a hotel, remember two words: Who says? Some ratings mean nothing, and some independent organizations do appraise hotels in a useful way. A traveler who knows the difference can avoid some disappointments.

One widely used hotel ratings source, though it’s largely invisible to consumers, is the Official Hotel Guide, a massive compendium found in the offices of travel agents. The hotel guide rates thousands of hotels worldwide on a 10-step scale. To profit from all that data, however, a traveler must realize that in the OHG’s polite language, “first class” is about the middle of the pack, and “moderate tourist class” is the bottom of the barrel.

By OHG’s definitions, the very best hotels are classified superior deluxe . Descending from there, one finds deluxe, moderate deluxe, superior first class, first class (dependable, comfortable places that “may be safely recommended to average clients not expecting deluxe facilities or special services”), limited-service first class, moderate first class, superior tourist class, tourist class, moderate tourist class (“Low-budget operations, often quite old and may not be well kept. Should only be used in a pinch if others are not available. Clients should always be cautioned what to expect.”) In the San Francisco market, superior deluxe rooms run about $200 nightly, first class hotels run around $100, and moderate tourist lodgings run around $50.

The best-known ratings in this country are the five-star system of Mobil Trade Guides (which dates to 1958), and the five-diamond system of the American Automobile Assn. (which dates to 1977). Both systems evaluate hotels and restaurants, and annually update their findings in guidebooks. Both rely on inspectors who make unannounced visits, and neither accepts payment from hotels in exchange for listing.

A five-star Mobil rating means the establishment is “one of the best in the country.” Four means “outstanding--worth a special trip.” Three: “Excellent.” Two: “Very good.” One: “Good--better than average.” Mobil says it gives most attention to facilities, furnishings and service, also weighing climate, historical, cultural and artistic variation as “major factors.” Mobil guides concentrate on properties in the United States.

Under the AAA system, five diamonds mean “an exceptionally high degree of service; striking, luxurious facilities, and many extra amenities.” Four stars: “a high level of service . . . wide variety of amenities and upscale facilities.” Three stars: “a degree of sophistication” beyond cleanliness and comfort. Two stars: Clean, comfortable and safe, with “noticeable enhancements in decor” but aimed at the budget-oriented traveler. One star: “good but unpretentious accommodations,” safe, clean and private, with “functional, clean and comfortable” rooms. AAA guidebooks cover the United States, Canada, the Caribbean and Mexico. (Responding to rising consumer safety concerns, AAA inspectors over the last two years have resolved that they won’t even look at properties that haven’t installed such safety features as dead-bolts and door-viewers in guest rooms.)

Among upscale travelers in Europe, Michelin guides are a widely venerated source of advice for their rigorous standards and unannounced inspections. The books are best known for grading restaurants, but Michelin’s inspectors also rate hotels. The logo ratings run from a tiny building with a five-peaked roof (meaning “luxury in the traditional style,” such as the Ritz in Paris and its $600-a-night rooms) to a squat building with single-peak roof (“quite comfortable,” usually with rates of $75-$100 nightly). There are also two lesser rankings--a roof over a drinking glass and fork, indicating “simple comfort” and an “M” in a box, indicating “modern amenities.”

Many foreign governments themselves maintain rating systems for hotels. The government ratings often rely exclusively on easily quantifiable characteristics--size of rooms, availability of elevators and so on--but the results can be helpful. In a survey earlier this year, editors at Consumer Reports Travel Letter found that the following governments run ratings programs: Australia, Austria, Belgium, France, Greece, Indonesia, Italy, Mexico (which last year hired AAA to rate its top 400-500 hotels), the Netherlands, New Zealand, Spain, Switzerland and the United Kingdom. (For more information, contact the relevant government tourist office.)