33 pages. "The worst-case mortality scenario in the perturbation analysis corresponds to an improved mortality trajectory, implying that a retiree's aversion against mortality uncertainty is translated into the fear of longevity risk in retirement planning.... Even under the presence of mortality model uncertainty, annuitization can still induce a noticeable increment in utility. The optimal annuity payout pathway increases over time as mortality rate grows and more uncertainty about the future is resolved during the later stage of retirement."  MORE >>