Kington highlighted a finding that nearly nine in 10 scientists reported they still intend to work at NIH a year from now. Despite rumblings of low morale, he said the scientists' job satisfaction rate of 81 percent reflects one of the government's most positive work forces.

Officials also emphasized employees' belief that the new rules will boost the agency's credibility with the public. Seventy-three percent of the employees who responded agreed with that, the survey found.

"We have to monitor closely and we'll continue do that, and if we show through our evaluations objective evidence of an impact on our ability to recruit and retain the smartest staff, scientific and nonscientific, that we can, then we will be the first ones to make the case for modifying the rules, but we're not there yet," Kington said.

One NIH administrator who left over the ethics rules said the agency's changes were handled poorly.

"Dedicated public servants were harassed right out of NIH. That's a disservice to us all," said Edward Maibach, the former associate director of the biggest NIH component, the National Cancer Institute. He is now director of Public Health Communication at the George Washington University. Maibach said he left the NCI nearly two years ago because new financial disclosure requirements invaded his privacy.

The changes are "a dramatic backlash," to earlier policies encouraging outside work by NIH scientists to speed practical application of scientific advances, he said.

Arthur Caplan, medical ethics chairman at the University of Pennsylvania, said tighter rules were needed but "we still haven't figured out exactly how to manage conflict of interest."

"To have a large number of the senior scientists unhappy spells trouble. You don't want them to retire or leave," he said.

"The leaders of the NIH and in Congress have to think a bit harder about giving a tiny bit of breathing room so that NIH scientists are not sent into a monastery from which they can't ever come out in the name of scientific integrity."