CAMBRIDGE, Mass.-For employers that want to move more workers into managed care, a curious paradox exists.

Survey after survey shows most employees are happy with their treatment in health maintenance organizations. But the public remains increasingly skeptical about whether the HMO industry is trustworthy.

So says Robert J. Blendon, professor of health policy and political analysis at Harvard University in Cambridge, Mass. Mr. Blendon said an analysis of survey research conducted over the past few years shows people form impressions of managed care based on worst-case scenarios of HMOs that have denied care or made mistakes with tragic results.

For benefit managers, such industry dynamics are important, because persuading employees to move from traditional indemnity health plans to managed care plans-and to stay in them-depends both on their satisfaction with their own plan and with managed care generally.

Mr. Blendon's presentation came at a seminar for the media, HMO executives and medical directors sponsored by the Washington-based American Assn. of Health Plans and Harvard's John F. Kennedy School of Government.

Regardless of people's own routine or pleasant experiences with HMOs, highly publicized cases of people being injured or dying as a result of HMO treatment have created lasting, negative images in the public's mind, Mr. Blendon said.

He cited a survey prepared by Louis Harris & Associates this year that showed only 51% of the public thinks HMOs and other managed care networks "do a good job" in serving customers, one of the lowest of all industries rated. That level of confidence was far below those expectations of good service from physicians, at 83%; drug companies, at 79%; and hospitals, at 77%. Health insurance companies drew a 59% favorable response.

According to Mr. Blendon, other surveys show that a majority of Americans believe their ability to get good health care is worse now than three years ago; that the U.S. health care system is partly good but needs some fundamental changes; and that government has a role in protecting consumers from unfair treatment at the hands of managed care plans.

Ironically, however, when questioned about their own experience with managed care, most people-especially those who have been healthy-give the system high marks, he said. Mr. Blendon said the cause of the discrepancy is plans that have fallen outside normal industry experience by becoming involved in outrageous controversies involving denials of care or allegedly poor treatment.

Mr. Blendon drew an analogy between recent HMO experience and the crash of ValuJet Flight 592 in the Florida Everglades in May 1996. Regardless of passengers' personal confidence in air travel before and after the accident, negative news about alleged ValuJet cost-cutting and its supposedly lax inspection record cast a shadow over the entire discount airline industry for a time, he said.

Mr. Blendon's remarks were echoed last month by David Mechanic, director of the Institute for Health, Health Care Policy and Aging Research at Rutgers University in New Brunswick, N.J. Writing in the Journal of the American Medical Assn., Mr. Mechanic noted the public's "growing ease of attributing dissatisfactions and perceived failures to clearly identifiable targets (indeed, an entire industry) than to a single professional, service, or institution."

With HMOs, Mr. Mechanic wrote, "the culprit is now more easily definable and each observable misdemeanor is a signal for what is wrong with managed care."

Part of the answer, Mr. Mechanic wrote, may be for managed care plans to regain respect by working more closely with physicians, increasing flexibility, and easing the "formal explicit rules" of capitation that are causing the public to mobilize politically against managed care.