Even in slow economic times, consumers for the most part continue to choose preferred provider organizations over other types of health insurance, even though the choice that PPOs give costs more, according to recent data.

Roberta Goodman, of Merrill Lynch, agrees, saying that "PPOs and hybrids will continue to be more successful in the marketplace than traditional gatekeeper HMOs."

Traditional indemnity plans have been the hardest hit.

In 1988, 73 percent of covered workers in the U.S. had indemnity insurance. That number is now 5 percent.

PPOs remain fastest-growing health insurance vehicle for covered workers

SOURCE: KAISER FAMILY FOUNDATION/HEALTH RESEARCH AND EDUCATIONAL TRUST SURVEY OF EMPLOYER-SPONSORED HEALTH BENEFITS, 2002