Check whether you’re demanding an unfair ambiguity premium

Estimate what you’d accept under comparable known-odds risk — if your bar is much higher for unknown odds, that gap is the bias.

Why it works

French and Poterba (1991) documented that investors demand excess return for foreign stocks over equivalent domestic ones — partly an ambiguity premium for the unfamiliar. The same dynamic appears in career, health, and relationship decisions: people demand far more evidence before acting in unfamiliar domains than familiar ones. When the premium is driven by unfamiliarity rather than genuine downside risk, it systematically filters out high-value opportunities in new domains.

How to do it

1. When hesitating, ask: what would I accept under a comparable risk with known odds?
2. Estimate your acceptance threshold for the familiar version and the unfamiliar version.
3. If the gap is large (2x or more), it likely reflects ambiguity aversion, not rational caution.
4. Decide deliberately: is that premium justified by genuine information asymmetry or just discomfort with the unfamiliar?

Evidence

French and Poterba (1991) documented home-country bias as large and unexplained by risk alone. Subsequent work attributed a portion to ambiguity aversion. The audit heuristic is practitioner-derived; no RCTs exist. (observational)

Not all ambiguity premiums are irrational: genuinely novel situations may warrant extra caution because the distribution of outcomes really is unknown. The check targets premiums above and beyond what the true uncertainty warrants.

Sources

• French, K.R., & Poterba, J.M. (1991). Investor diversification and international equity markets. American Economic Review, 81(2), 222–226.

Common mistake

Comparing the unfamiliar option to an idealized familiar option rather than a comparable one — the comparison must hold objective risk level constant.