The "electronic office" that has promised to make American business more productive has given employers unprecedented opportunities to monitor -- some say spy on -- the minute-to-minute performance of millions of American white collar workers.

A recent congressional report concluded that up to seven million U.S. workers are being monitored electronically, often without their knowledge. The phenomenon is causing growing concern among unions, civil liberties groups and legislators.

Critics say the workers most subject to electronic supervision are poorly paid, relatively unskilled women. Some activists and mental health professionals say awareness that they are being monitored dramatically increases stress in these workers, sometimes with negative effects on their productivity.

Karen Nussbaum, executive director of 9 to 5, National Association of Working Women, said such monitoring has led to "health problems, more sick time and higher turnover rates" among some workers. "Often the stress of monitoring actually stands in the way of productivity," she said.

No scientific studies have linked such monitoring with worker stress, said Michael Smith, a University of Wisconsin professor who contributed to the congressional study, but anecdotal testimony "highlights very important issues."

Employers say the surveillance increases productivity, improves quality control and provides an objective system of worker supervision.

At Pacific Southwest Airlines, which monitors both telephone and computer use by its service representatives, spokesman William Hastings said, "Our customer complaints have gone down since we've instituted monitoring. Our productivity numbers have improved markedly." Electronic monitoring also "takes the subjectivity out of" supervision.

While electronic monitoring affects only a small portion of today's labor force -- primarily in data processing, insurance, airlines, telemarketing and telephone service -- specialists are concerned about its invasive nature and because its targets are the least secure and most vulnerable workers. Noting that technology makes it possible, for instance, to count automatically a computer operator's keystrokes as a measure of productivity, critics are focusing on issues such as these:

The pace of work is driven by computers without regard to the peaks and valleys of workloads or the needs of workers.

Telephone conversations of airline reservations clerks, telephone sales people, operators and others are monitored -- often without the knowledge of employes or customers -- to check on the manner and speed with which calls are handled.

In the name of controlling costs, some firms keep logs of all employe telephone calls. Critics call such records, including the numbers called, a serious potential intrusion into privacy.

In its report, titled "The Electronic Supervisor: New Technology, New Tensions," the Congressional Office of Technology Assessment noted that 20 percent of U.S. workers hold clerical jobs. There are no constitutional safeguards for workers in the private sector, the report noted, and most clerical workers are not covered by collective bargaining agreements.

Eighty to 90 percent of 110 companies surveyed for the report by professor Alan Westin, a privacy specialist at Columbia University, reported collecting electronic performance data on employes. A quarter of them said the data was used only for aggregate planning and cost controls; the others said they used it to evaluate workers.

Robert Grasing, a consultant whose Simsbury, Conn., firm develops electronic work measurement systems and has consulted for about 300 companies, mostly banks and insurance firms, said proper worker-monitoring can improve productivity 20 percent to 35 percent.

Grasing, a senior vice president at Robert E. Nolan Co., says the success of monitoring depends on the timeliness and the quality of feedback from supervisors. Monitoring workers as they perform a task -- rather than later -- enables a supervisor to help an employe who has a personal problem or trouble with a task, he said, adding, "The best way to use such information is to counsel people at the time they are having difficulties."

Toni Watson, a reservations clerk at Pacific Southwest Airlines in San Diego, thinks monitoring is counterproductive. "My numbers may have improved since monitoring began, but I'm certainly not a better worker," said Watson, who is active in the 9 to 5 group. "I get customers on and off as fast as I can. Sometimes I take time with people, especially elderly customers, who are confused by the wacko fare structures. But then I know I have to make up the time with others or accumulate demerits and face discipline."

Watson said she was especially disturbed by her company's mistrustful attitude. "If I come back late from a break, they'll plug into my set all day. If you chat with your neighbor, the supervisor will say, 'We heard you talking about what you're going to have for Thanksgiving dinner.' "

Hastings, Pacific Southwest's director of corporate communications, said productivity records are not used to discipline employes.

"We instituted electronic monitoring to take the subjectivity out of supervisors monitoring workers," he said. "The system was designed to help employes meet their productivity standards. In the past, monitoring by supervisors was very subjective, a real hit or miss situation. Now employes have clear, objective standards."

Telephone conversations are monitored periodically to make sure employes are using the right language, he said. "We just want to make sure the standard sales pitch is being used."

He dismissed complaints that timing calls prevents proper client service. "When we set the amount of time allowed for calls, we factored in extra time for providing information. If you average the calls over a week, you find there is ample time to provide customer service."

In Boston, an area sales representative for AT&T said monitoring of workers' calls there creates a climate of mistrust. "It's a terrible invasion of privacy -- both for workers and for customers who don't know they're being monitored," said the woman, a four-year AT&T employe who asked not to be identified. "It's not necessary for quality control. Supervisors call back customers to ask if they're satisfied with the service. Managers periodically call up pretending to be customers. I don't see why, with those backup checks, they have to monitor."

Terry Romano, an AT&T spokesman, dismissed concerns about invading customer privacy. AT&T opposes a bill, proposed by U.S. Rep. Don Edwards (D-Calif.), that would require an audible signal to alert parties that their calls are being overheard. "I think a beep on the line would just be an annoyance," Romano said.

He said monitoring provides a tool to ensure quality service. Because employes know there's monitoring, the practice engenders no mistrust, he said. "They know it's only a tool to help them do their jobs better."

Two psychologists who have studied the issue said the timing and quality of feedback from supervisors is critical.

Dr. Lawrence Schleifer of the National Institute of Occupational Safety and Health is heading a study of the effects of feedback on job stress. He said evidence indicates that regular, objective feedback on job performance reduces anxiety and sustains motivation. Schleifer said preliminary results from one continuing experiment with data entry clerks indicate that ongoing, current-time, electronic feedback can have a "positive effect on performance motivation and can reduce levels of stress."

The alternative, he said, is a system in which workers would be told at the end of, say, a month, that they didn't meet their work standards. "All a worker in that situation can do is get angry and frustrated," he said.

Dr. David Keenan, a California psychologist who sees a number of patients whose work is electronically monitored, agreed that feedback from electronic monitoring does not necessarily induce stress. Only when coupled with negative feedback does it create emotional problems, he said. "When a person's work is monitored on a second-to-second basis, and the feedback is used to criticize his behavior, it is similar to a rat in a chamber who is subjected to random shocks. The situation causes autonomic, physiological stress arousal."

He said people often work at varying levels of effort, and electronic monitoring, which measures performance on a second-to-second basis, can be emotionally destabilizing, especially when used punitively. Monitoring coupled with positive, encouraging feedback, he said, need not be stressful at all.

Grasing, the Connecticut consultant, said the issues raised by the congressional report "are issues of management, not technology.

"If management uses numbers only, they're going to be misapplying the information. Some firms buy the {monitoring} systems without the management training needed to apply them properly."

Concluded Schleifer: "In most cases, managers want to use monitoring technology to boost productivity. But they don't have an appreciation of the human factor in all of this. A worker is more than an appendage to the technology.