How should the pros be rated? Prorate 'em, that's how.

In the NBA, instead of asking only how many points, rebounds or assists a player gets per game, we also should ask how many he gets per minute.

"Production-per-minute is the best way to evaluate a player," says Bob Ferry, the Bullet general manager, "but almost nobody takes the time to do it."

For instance, in baseball no one would dream of figuring a player's batting average by comparing his hits to how many games he played. It wouldn't be fair. Naturally, you make a ratio out of hits and at bats.

Yet, in the NBA, players are judged statistically on per-game averages, disregarding the huge differences between men who play 40, 30 or 15 mnutes per game.

Indeally, two kinds of statistics -- total production (i.e., per game averages) and rate of production (averages pro-rated over 48 minutes) -- would complement each other to give a well-rounded picture.

"I work out prorated stats, bassed on what a guy would do if he played the full 48 minutes, for all the teams we're just about to play," says Ferry. "That's the only way to get a true profile of each guy's role and his contribution.

"But it's impossible to get up-to-date prorated stats for the whole league. They don't exist."

Well, now they do (thanks to my pocket calculator and numb fingers): hot off the presses, the NBA's midseason prorated statistics, complete through games of Jan. 7.

Two types of discoveries emerge from these new stats.

First, we find a "subculture" of part-time players who, in their restricted way, are stars at special phases of the game.

For instance, on a per-minute bases, Mark Landsberger has a better rebounding average than Moses Malone; Harvey Catching blocks more shots than Kareem Abdul-Jabber; Dudley Bradley is the NBA's best ball thief; and Steve Mix and Purvis Short each score 32 points for every 42 minutes they get to play. On Ferry's Wastington team, Roger Phegley (27.77), not Elvin Hayes (27.08), has the highest prorated scoring average.

Second, we see the NBA's familiar cast of superstars in a slightly altered way with the new shadings between them and new grist for argument.

For instance, of the top 20 scorers, who gets his points while taking the fewest shots? By an almost amazing margin, it is Adrian Dantley, who, on a prorated bases, needs only 24 shots to produce 35 points.

Almost every basic statistical category has its surprises. Who would guess that both Swen Nater (20.49) and Chicago's anoymouns 6-foot-8 Landsberger (19,58) would have higher prorated rebound averages than Malone (18.89)?

The NBA's leading shot-blocker, Abdul-Jabber, ranks only fifth per-minute, behind George Johnson, Catchings, Tree Rollins and Joe Meriweather.

In scoring, the game's glamour arena, the NBA has 19 "fill-it-up" guys who prorate as 30-point scorers.

The top four are predictable: George Gervin (41.76), Lloyd Free (38.86), Julius Erving (35.36) and Dantley (34.92). But of the next four best instant-offense men, only Walter Davis (12th) is among the NBA's top 20 "regular" scorers: Davis (34.8, prorated), John Drew (34.6), Freeman Williams (33.98) and Mix (32.0).

Also among those 19 best point machines are several others who can't be found on conventional lists of leading scores: Ray Williams (31.4), Short (31.5), Mike Mitchell (30.4) and Mike Newlin (30.2).

Prorating is best at singling out unsung skills.

No one, for example, can approach Lloyd Free's knack for drawing free throws -- 14.97 per 40 minutes. Why do they think them Free throws?

How can Cornbread Maxwell be Boston's second-highest scorer when his shots per 48 minutes (14.0) are so infrequent compared to the league's true gunners like Gervin (31.6), Freeman Williams (30.2) and Erving (29.1)?

If prorating reveals that New York's Mike Richardson is second in the NBA in both steals (4.48) and assists (12.02), it also is adept at fingering the league's culprits, and its oddities.

Who are pro basketballs fumble fingers? George McGinnis (5.98) and Mickey Johnson (5.68) are the leaders in turnovers.

And the worst foulers, the hatchet man who can't tie their shoes without drawing a whistle? Well, Seattle's Tom LaGarded (8.62) and San Antonio's Paul Griffin (8.38) might foul out of every game if they tried to play every minute.

Who has the fewest steals and the fewest assists, prorated, in the NBA? Once again, our new friend Landsberger with 1.4 assists and 1.0 steals. Maybe that's why the Bulls play him only 23 minutes a game.

Who are the guys who need a written from the coach before they are allowed to shoot? Paul Silas (7.79) and Catchings (8.88) have the fewest shots per 48 minutes.

And, trick question, the worst shot-blocker in the NBA?Try Nate Archibald, who has blocked one shot in 1,504 minutes. Who in the world did Tiny stuff?

It is impossible to resist the temptation to creat prorated all-star teams.

For an All-Sub team of little-noticed players who are not in their team's top five in minutes played, why not have Cathchings at center, Landsberger and Mix at forward with Bradley and Housten's Split Levell (high in assists and steals) at guard.

Our All-Unknown Starters would include Nater at center, Mitchell and Short at forward and Richardson and Newlin at guard.

As for the invevitable All-Overrated team, let's start with Freeman Williams and Super John Williamson at guard -- a pair of ball hogs who prorate at 30 and 28 shots per game while having scoring averages of less than 18 points a game.

At forward, why not McGinnis and Rick Barry, whose pathetic mark of seven rebounds per 40 minutes is the worst of any NBA front-court starter. Barry replaces the retired Cazzie Russell as the pros' most reluctant rebounder.

At center, the dishoner goes to Boston's Dave Cowens. His 11.2 rebounds in 48 minutes are the fewest of any pivot man, and fewer than most power forwards as well.

Lest anyone become too enthusiastic about the concept of production-per-minute and prorating, one statistic should suffice to put it back in perspective with all the other evaluative variables that NBA fans use in debate.

Who is the NBA's best prorated assist man (12.85), and, thus, in theory, its's best team player? That's right -- the No. 1 man on the Bullet shelf, Kevin Porter.