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.
Key takeaways
- What it is: 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.
- Evidence: Backed by observational / correlational evidence.
- Avoid: Comparing the unfamiliar option to an idealized familiar option rather than a comparable one — the comparison must hold objective risk level constant.
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
- 1When hesitating, ask: what would I accept under a comparable risk with known odds?
- 2Estimate your acceptance threshold for the familiar version and the unfamiliar version.
- 3If the gap is large (2x or more), it likely reflects ambiguity aversion, not rational caution.
- 4Decide deliberately: is that premium justified by genuine information asymmetry or just discomfort with the unfamiliar?
What the evidence says
ObservationalFrench 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.
Honest caveat: 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.
- — 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.
IX Coach surfaces a comparison prompt: “What would you accept if the odds were known?” making the ambiguity premium visible and auditable.
Practice this with IX Coach →