A shift last year by the Social Security Administration to limit access to its death records amid concerns about identity theft is beginning to hamper a range of research, including federal assessments of hospital safety and efforts by the financial industry to spot consumer fraud.

For example, a research group that produces reports on organ transplant survival rates is facing delays because of the extra work it must do to determine whether patients are still alive. The federal agency that runs Medicare uses the data to determine whether some transplant programs have such poor track records that they should be cut off from government financing.

“We are not going to be on time until this problem is corrected,” said Dr. Bertram L. Kasiske, a Minneapolis nephrologist who directs the research group, the Scientific Registry of Transplant Recipients. “It’s a big deal. A lot of people look for these reports and depend on them.”

Other medical researchers, including those conducting long-term federally financed studies of cancer and cardiovascular treatments, said the changes imposed last November were now slowing their work significantly. And a spokesman for financial industries like life insurance, banking and credit services said the change was making it more difficult to detect identity thieves who steal names and Social Security numbers from the deceased.