Relatively few people who have retirement savings plans such as the TSP and 401(k)s actively manage them, says a survey that recommends paying more attention to investment results and reacting accordingly.

In the TSP, for example, a relatively small minority of investors were so active in moving funds at one time that the program imposed limits on how many transfers were allowed per month. Similarly, officials say that it’s a relative few who are pushing, although vocally, for greater investment choices through the planned mutual fund “window.”

The recent report by the Aon Hewitt consulting firm examined programs of 138 employers with 3.5 million eligible workers, finding that in 2014 only 15 percent of workers rebalanced their portfolios. Setting aside investors who are fully invested in target date funds comparable to the TSP’s lifecycle L funds, only 19 percent rebalanced their portfolios.

“In the last decade, employers have made strides in helping workers prepare for retirement by adding plan features that make saving and investing easier,” the company said “At the same time, employees continue to take a passive role in managing their 401(k) plans.”

“Workers who took advantage of help tools, in the form of managed accounts, online advice and target-date funds, fare better than those who go it alone. Providing these resources allows workers the benefit of professional management, in order to optimize their returns,” it added.

The TSP is planning to add such services but that is a long-term project with many questions still to be answered regarding exactly what it will do, and how.