Why Even the Best Retirement Calculator is Wrong
Roger Whitney explores why retirement planning software—especially Monte Carlo simulations—can give a false sense of confidence if misunderstood. He explains what these tools actually measure, the hidden assumptions behind them, and why retirement is a complex problem that requires judgment, flexibility, and resilience—not just a high “success rate.” Roger shares how to properly interpret results, avoid common traps, and use software as a guide rather than a decision-maker so you can build a retirement plan that supports a great life. OUTLINE OF THIS EPISODE OF THE RETIREMENT ANSWER MAN (00:00) This show is dedicated to helping you not just survive retirement, but have the confidence to lean in and rock it. (00:30) Roger introduces the episode topic—why your retirement calculator’s success rate can be misleading. PRACTICAL PLANNING SEGMENT (02:50) Roger explains his perspective as a long-time practitioner and outlines his experience using Monte Carlo-based retirement tools. (05:05) Complicated vs. complex problems: why retirement can’t be “solved” like a math equation and must instead be managed over time. (09:30) Concerns about overreliance on software—from advisors scaling businesses to individuals misinterpreting results. (11:30) What retirement software actually measures. (13:25) What software does NOT measure. (14:18) Best uses of planning software. (17:40) What software should NOT be used for. (19:40) Key dangers of using retirement software. (23:00) Feasibility vs. resilience: why a plan that “works” on paper may still be fragile in real life. (24:20) The real risk: Overspending early and jeopardizing later years Underspending and missing out on life (26:20) The massive number of assumptions behind every plan—and how small changes can dramatically alter outcomes over time. (38:20) How to interpret results properly. (40:55) Looking beyond the number: evaluating the distribution of outcomes and plan sensitivity. (44:43) Understanding failures: Timing (early vs. late failures) Severity (minor shortfall vs. major gap) (48:27) Best practices: Hold success rates lightly Keep plans simple Regularly review assumptions Avoid over-planning and constant tweaking Define what success actually means for your life SMART SPRINT (56:04) Schedule time to review the assumptions in your retirement planning software—focus on understanding the inputs rather than optimizing the output. CLOSING THOUGHTS (56:50) Roger shares an update on the merger of his firm with Tanya Nichols’ firm and the creation of a new company, Retire Agile. REFERENCES livewithroger.com — Register for Noodle Live on March 28! Submit a Question for Roger Sign up for The Noodle