Tennis ratings. Some players judge an entire life's worth by the big board, while others show them as little concern as they would a penny in a crowded crosswalk. To go down is cause for tears and possibly some broken strings; to go up is sure reason to celebrate. Tournaments and matches are made on them.

Who does the ratings? A computer now, using a software program designed and written by a Salt Laker - Larry Jones.In March, during United States Tennis Association meetings in Hawaii, Jones was informed that his software-rating package - CompuRank Systems - had been officially adopted for national use. He said presently there are 20 sites around the western United States using his package. Ultimately, he hopes to have between 150 and 200 on the network.

Once in the system, a player from Utah could travel to New York and, matching ratings, come up with a competitive match. Or he could do the same right here in Utah.

Ratings began several years ago. It is a numbering system that classes players by ability. It goes from 2.0 to 7.0, with the 2.0 being an entry-level player and a 7.0 being the world's top pros. Most players, about 70 percent, said Jones, fall between a 3.5 and 4.0.

When the rating system - called the National Tennis Rating Program - first started, trained tennis experts watched and then rated players. "But what we found was that a person rating players here rated differently than one in New York or California," he said.

Now it's done by computer.

The system is based on competition and what Jones says is the value of a break . . . "about a tenth of a point." A 6-4, 6-4 score, for example, would be a two-tenths benefit to the winner, while a 6-1, 6-1 match would be worth about a five-tenths advantage.

The computer looks at the scores and the individual players and then comes up with a number between 2.0 and 7.0. That is the player's ranking.

All this, added Jones, works off national tournaments as the base. Players there are visually rated and then given absolute ratings. These are entered into the computer, which in turn spreads its way down the records to rate the players that played against the player with the absolute rating, then the players each of those played against, and so on until the entire season is matched and compared, and each player has a rating.

How accurate the rating is depends, of course, on the player. Fewer than five matches in the books, said Jones, will not give a true evaluation. "In these cases we try to look at the player and determine the rating. The more matches a player plays, then the more accurate the rating . . . within one-tenth of what you would call their `real' rating," he said.

There are rating clinics for those not in the system. The next will be May 12 at Oak Hills Tennis Center between 6 an 9 p.m. Trained rating personnel will be there to watch players and assign them an introductory rating. From there on it's a matter of wins, losses and how the computer sees them.