The American economy could experience painfully slow growth and stubbornly high unemployment for a decade or longer as a result of the 2007 collapse of the housing market and the economic turmoil that followed, according to an authority on the history of financial crises.

That finding, contained in a new paper by Carmen M. Reinhart, an economist at the University of Maryland, generated considerable debate during an annual policy symposium here, organized by the Federal Reserve Bank of Kansas City, which concluded on Saturday.
The gathering, at a historic lodge in Grand Teton National Park, brought together about 110 central bankers and economists, including most of the Federal Reserve’s top officials. In 2008, the symposium occurred weeks before the Lehman Brothers bankruptcy nearly shut down the financial markets. At the symposium last year, officials congratulated themselves on weathering the worst of the crisis.
But the recent slowing of the recovery cast a pall on this year’s gathering. As economists (some wearing jeans and cowboy boots) conferred on a terrace with a sweeping view of the 13,770-foot peak of Mount Teton, or watched a horse trainer tame an unruly colt at a nearby ranch, they anxiously discussed research like Ms. Reinhart’s. (Participants pay to attend the event, which is not financed by taxpayers, a Kansas City Fed spokeswoman emphasized.)
“I’m more worried than I have ever been about the future of the U.S. economy,” said Allen Sinai, co-founder of the consulting firm Decision Economics and a longtime participant in the symposium.