Defined contribution retirement plan managers may not be giving much thought to income planning or to the possible effects of disability on contributions.

Researchers in the San Francisco office of Buck Consultants L.L.C., a unit of Affiliated Computer Services Inc., Dallas, included questions about those topics in a recent survey of managers of 255 U.S. retirement plans.

Down in the trenches, retirement plan managers say the worst enemy is sloth.

Although 55% of the survey participants said their top defined contribution plan concerns include employees’ low average savings rate and 42% worry about lack of diversification in employees’ investment allocations, 80% agreed that their top concerns include “employee inertia/inattentiveness to retirement income needs.”

“Lack of lifetime income flow feature” was a top defined contribution plan concern for only 4.4% of survey participants, and “lack of disability income protection” was a top concern for only 1% of the participants.

Although 58% of the participants said their plans had changed investment fund menus in 2006 and about 12% said their plans had added a Roth feature, only 1.4% said their plans had arranged for an annuity purchase option, and only 1.4% had added an option for employees to buy disability insurance for plan contributions, the Buck researchers report.