Drug testing, routinely criticized as invasive, expensive, and inaccurate, is still the best way to ferret out drug abusers. But is that the real goal? After serious consideration, Purgatory Resort, in Durango, Colo., and Assets Protection, in Penndel, Pa., both have decided against using random drug testing in favor of computer-based performance testing.

"Our industry is moving toward drug testing," says Tammie Fry, human-resources director at Purgatory, a ski and summer resort. "But we don't feel it addresses the issue of safety. The majority of accidents are caused by stress and fatigue, not substance abuse." Robert Lubkay, president of Assets Protection, a security company, wanted a test "that gives immediate results and gets away from the invasive nature of drug testing." Here's how the tests they chose work:

· Purgatory uses a PC-based screening program called Factor 1000, developed by Performance Factors, based in Golden, Colo. Employees in such safety-sensitive jobs as ski-lift operation and child care complete a training program and then, by tracking a cursor across a computer screen, set their own baselines on the system. Each day, some 250 of the company's 700 employees take the test before they clock in at one of 18 tracking stations. The test takes less than a minute, and employees have eight chances to meet their baseline scores. If they don't, they're either assigned different responsibilities or sent home.

Fry says employees "overwhelmingly supported the idea over random drug testing." Computer-based performance testing, she says, is also cheaper. According to Performance Factors vice-president Terry Watson, the total cost is about $130 per employee for the first year, declining to $64 for each of the next two years and $27.50 every year thereafter.

· Assets Protection uses Delta-WP, produced by Essex Corp., in Columbia, Md. Roving supervisors with laptop computers randomly test the cognitive skills of the company's security guards. The employees analyze images and sequences of numbers or letters, and their scores are compared with previously set baselines.

"Employees like it," says Lubkay. "It's like a computer game, and it's far more pleasant than the alternative." He paid about $3,000 for the software, which he runs on three computers. He's confident the program deters drug and alcohol abuse, and, he says, "our clients love it."