Presidents at universities in the United States are lasting for shorter and shorter terms because of stress and other problems, largely because boards of trustees are doing a poor job of finding the right candidates for the positions, according to a report.
On average, they remain in the job for just under seven years. About half serve fewer than five years.
The study calls the typical USuniversity presidency a "revolving door", in which turnover is so high that it has become destabilising and demoralising to the institutions.
"Many presidential transitions are untimely, poorly managed, personally dissatisfying and in some cases even demeaning for the primary players - the presidents themselves," the report, by the American Association of State Colleges and Universities, concludes.
Presidential Succession: Beginning, Ending, and Beginning Again is based on surveys of presidents, and interviews with former presidents and the consultants who help fill these posts.
"Transitions have implications that go far beyond the president who's leaving and the president who's coming aboard," said John W. Moore, former president of Indiana State University and co-author of the report.
"These changes have a ripple effect through the organisation, and when they're handled poorly, you often see the departure of some of the most talented individuals at the institution," he said.
And such transitions are often handled poorly, according to Dr Moore and his co-author, Joanne Burrows, who chairs the department of educational leadership at Indiana State.
Dr Moore said boards of trustees, who generally hire the presidents, define their task very narrowly. "They don't really put the search and selection process into a broader context of transition management, where you're dealing with issues related to what are current institutional priorities that have to be attended to, what decisions should be made, what decisions can be postponed."
As a result, "presidents are chosen who are a mismatch for the institution".
This comes at a time when American university presidencies are becoming considerably more challenging than in the past.
Dr Moore said: "Universities are economic enterprises, so the president is also the CEO. And universities are much like small cities, where the president's job is that of a political leader."