4 percent rule still valid for income planning strategies

The report adds that advisors should only recommend withdrawals of three percent or less for the most risk-adverse retirees or when investment returns are "well below" the historical average. Conversely, initial drawdowns exceeding 5 percent would be suitable for risk-tolerant investors who can accommodate changing market returns.

Turning to average and worst-case scenarios, the research observes that a constant percentage ("floor") strategy yields the highest average utility score for many historical periods. Combining elements of a constant dollar and constant percentage strategy, the floor strategy establishes a minimum withdrawal, but permits greater spending when returns are above average.

The report cautions, however, that the strategy can exhaust assets when the floor is set too high and returns are poor.

"This strategy would have fared well for all retirements from January 1930 through June 1935, lasting at least 40 years," the report states. "This strategy would have exhausted assets, however, after only 23 years for retirements beginning in November or December 1936. It's a relatively high-risk strategy that would have happened to perform well on average during the historical simulations."