There are deals to be had by booking hotel rooms online, but don't assume four stars to them means the same as it does to you.

Everyone loves a bargain, and when I recently secured a rate of US$81 per night for a four-star hotel in San Francisco through Priceline.com, I did a dance around my living room. I had never stayed at that particular hotel before, but given its star rating, I knew what to expect. Indulgent toiletries, fluffy bathrobes, room service, swimming pool, here I come!

The hotel turned out to be a fantastic, regal property. It met my expectations in every way–except that there was no pool. A minor letdown, given how satisfied I was with the quality for the price. But aren't four-star hotels supposed to have pools?

Back on Priceline.com, I trawled the fine print. I was surprised to learn that the site's hotel classification is not based on a universal system derived from a checklist of amenities and services. Rather, Priceline uses its own one-to-five-star system "based on evaluations performed by Priceline, incorporating feedback from our customers".

After more research, it hit me: there isn't just one system, there are galaxies.

"There are a lot of standards all over the world," confirms Anthony Pollard, president of the Hotel Association of Canada, on the line from Ottawa. "Some are done by governments, some are done by the operators, some are done by industries. It's a hodgepodge."

Like Priceline, Expedia and Travelocity each use their own system. According to Expedia's Web site ( www.expedia.ca/ ), its ratings are generated from "a wide variety of factors, including ratings from independent ratings systems, media recognition, and post-trip surveys of our customers". Expedia gives general descriptions of what to expect at each star level but specifies that "star ratings do not necessarily reflect all the amenities or services that might be available at a hotel, and some amenities and features may not be available in every room or at every property with a particular star rating."

Travelocity ( www.travelocity.ca/ ) rates its properties using a combination of its own and Northstar ratings. The latter are assessed by Northstar Travel Media, which "provides ratings for more than 40,000 properties around the world.... Principal sources used in determining classifications include reports from representatives, local and regional organizations as well as information from the hotel."

It's hardly surprising, then, that a hotel can be awarded different star ratings under different systems. Pollard recommends checking a hotel's rating in the Canada Select star system ( www.canadaselect.com/ ) or the AAA diamond system ( www.aaa.com/ ), the industry-accepted systems for North America. "The standards are very, very clear...the whole idea being that the person travelling is going to know what he or she can expect when they arrive.... For example, at a five-star hotel you will have a doorman around the clock, you will have a chef in the kitchen who can prepare a hot meal for you and bring it to your room."

So why didn't my hotel, rated four stars by Priceline and four diamonds by AAA, have a pool? "There are occasionally exceptions," Pollard says, like grandfather clauses for heritage properties. "An example is the [Royal Méridien] King Edward hotel in Toronto. It's a top-of-the-line, four-diamond property. It doesn't have a swimming pool. Why? It was built in the 1800s."

So let the stars guide you, but if you really want to know if there's swimming in your future, call the hotel.