Episode 391: How Assumptions Shape Financial Planning Outcomes

Episode Summary

Executive Summary: This episode examines how financial-planning assumptions shape outcomes, using perspectives from planning, actuarial science, engineering, and retiree-focused advice. The guests argue plans are always wrong in detail but still useful when assumptions are credible, material, and stress-tested. They emphasize discovery, behavioral coaching, and revisiting plans as goals, client circumstances, and market conditions evolve.

Main Topics: Why assumptions matter in financial planning (Priority: 5/5): Aaron frames assumptions as the bridge that brings tomorrow into today, stressing that plans must be directionally and materially accurate rather than perfectly predictive. How different disciplines set assumptions (Priority: 5/5): Joe approaches assumptions conservatively from an actuarial lens, Brayden uses an engineering mindset focused on expected and unexpected outcomes, and Adam centers retiree behavior and spending realities. Client objections, biases, and discovery (Priority: 5/5): The panel discusses how objections often reflect alternative assumptions, how recency bias affects inflation views, and why planners should use conversation and behavioral interviewing instead of only questionnaires. Limits of planning software (Priority: 4/5): The guests argue software is useful but incomplete because it cannot fully capture behavior, family dynamics, or the uncertainty embedded in life and retirement decisions. Planning for the right question (Priority: 5/5): A major theme is that assumptions should change depending on the decision being answered, such as longevity for plan viability versus expected outcomes for withdrawal sequencing. Planning as an ongoing process (Priority: 4/5): The conversation repeatedly emphasizes that financial planning is not a one-time event; assumptions, goals, spending, and market expectations should be updated as reality unfolds. Professional identity and success (Priority: 3/5): In the closing roundtable, each guest defines success in terms of impact, sharing knowledge, helping clients, and living a balanced life rather than maximizing money alone.

Key Arguments: Assumptions are foundational because they shape the story a plan tells and the decisions clients make; they must be backed by credible data and pass stress tests. Financial plans are never perfectly right, but they can still be useful if they are materially accurate and revisited over time. Investment return and inflation are the most important starting assumptions, but the appropriate level depends on the client’s actual risk exposure and goals. Engineering and actuarial thinking both highlight that models should anticipate both expected and unexpected outcomes, not just the average case. Clients often challenge assumptions because they are expressing their own hidden assumptions or fears, especially around longevity and inflation. Risk tolerance questionnaires are helpful but insufficient; planners should rely more on discovery, context, and holistic interviewing. Software is a tool for analysis and communication, not the planning process itself; the planner must decide what to model and why. Retirement spending often declines in real terms over time, so software assumptions that assume static or rising real spending can misstate outcomes. Different planning questions require different assumptions; for example, a conservative longevity assumption can support plan viability, while expected longevity may be better for withdrawal sequencing decisions. Plans should be updated when material life events occur, when the question changes, or when research and market conditions materially alter the underlying assumptions.

Data Points: Longevity assumption challenged by planners: 58% - Aaron reports that 58% of planners in the room said longevity was the assumption clients challenge most. Retirement spending decline: ~1% per year - Adam cites behavioral research suggesting retirees reduce spending by roughly 1% annually through retirement. Risk tolerance questionnaire study sample: 131 questionnaires - Aaron references a U.S. study examining variance across 131 different risk tolerance questionnaires. Planning experience window: 35+ years - Joe has worked in pensions, DC programs, and retiree health plans for over 35 years. Ages discussed for longevity behaviors: 60s vs. 75-80 - Adam describes a pattern where people think they will die earlier in their 60s, then later believe they may live longer once they survive that age range. Projection assumption updates at PWL: Twice a year - Ben notes that PWL updates expected return assumptions twice annually, with ad hoc updates in extreme events. Projected plan evaluation timeframe for some clients: 2-5 years - Adam says some clients near retirement are working on plans over a two- to five-year horizon. Informal audience polling range on discovery time: 0% to 90% - Aaron says audience responses ranged widely when asked how much time planners spend going deep with client discovery.

Pivotal Quotes: "Assumptions are the bridge that brings tomorrow into today." — Aaron Thieid: Aaron explains why assumptions are central to financial planning and decision-making. "Every single plan presented to a client should say this plan is wrong, but it's the best we have today." — Joe Newton: Joe summarizes the uncertainty inherent in planning and why plans must be treated as living processes. "The planning software does not dictate the planning process." — Brayden Warwick: Brayden explains that the planner must reconcile software outputs with human behavior and practical feasibility.

Implications: Listeners should treat financial plans as evolving decision tools, not predictions. For the industry, the episode reinforces that technical modeling must be paired with behavioral discovery, materiality, and ongoing updates as clients, markets, and goals change.