{"id":1086,"slug":"brown-imai-vieider-camerer-2024-meta-analysis-lambda-1955","title":"Brown, Imai, Vieider, Camerer (JEL 2024) — meta-analysis of 607 loss-aversion estimates; mean λ = 1.955, CI [1.820, 2.102]","kind":"reference","scope":"business","status":"current","audiences":["kevin","candid-team"],"topics":["psychology-aversion","behavioral-economics"],"reference_body":"**Claim:** The most comprehensive synthesis of empirical loss-aversion estimates to date. Brown, Imai, Vieider, and Camerer (2024) draw on **607 empirical estimates from 150 articles** spanning economics, psychology, and neuroscience (studies 1992–2017). They report a mean loss-aversion coefficient **λ = 1.955** with a 95% credible interval of **[1.820, 2.102]**.\n\nThe canonical Tversky-Kahneman 1992 estimate of λ = 2.25 — the \"losses loom twice as large as gains\" rule of thumb that has dominated marketing-strategy discourse for three decades — **falls outside this credible interval**.\n\n**Source:** Brown, A. L., Imai, T., Vieider, F. M., & Camerer, C. F. (2024). \"Meta-analysis of Empirical Estimates of Loss Aversion.\" *Journal of Economic Literature* 62(2): 485–516. https://www.aeaweb.org/articles?id=10.1257%2Fjel.20221698\n\n**Confidence:** Verified.\n\n**Caveat:** Brown et al. note that \"few characteristics are substantially correlated with differences in the mean estimates.\" We cannot confidently claim GCs as a population show higher-than-average λ, though it is plausible given high-salience loss exposure. Research gap.\n\n**For Candid:** The \"loss is 2× a gain\" rule is defensible as rough magnitude but not as precise multiplier. Stop citing \"losses loom twice as large as gains\" as if it were a precise constant — it overstates the empirical mean by ~15%. The directional point (loss aversion is real and substantial) remains.\n\n**Refines:** [[kahneman-tversky-prospect-theory-loss-aversion-2to1]].","rationale_body":null,"metadata":null,"links":{"outgoing":[{"slug":"research-brief-risk-aversion-post-failure-may-2026","title":"Research brief: risk aversion, loss aversion, and post-failure decision patterns in GC and trades-business decision-makers (May 2026)","kind":"reference","scope":"business","link_type":"relates-to"},{"slug":"kahneman-tversky-prospect-theory-loss-aversion-2to1","title":"Kahneman & Tversky prospect theory (Econometrica 1979; JRU 1992) — loss aversion ratio ~2:1; fourfold pattern; certainty effect","kind":"reference","scope":"business","link_type":"relates-to"}],"incoming":[{"slug":"overconfidence-in-house-comparator-pattern-for-gc-pitches","title":"The \"my nephew can build it\" pattern — loss-aversion on the invoice + overconfidence on in-house execution as mechanistically linked","kind":"reference","scope":"business","link_type":"depends-on"},{"slug":"rule-price-in-affordable-loss-terms-not-expected-return","title":"R1 — Price and scope in affordable-loss terms, not expected-return terms; headline = \"maximum you can lose,\" not \"projected upside\"","kind":"rule","scope":"business","link_type":"depends-on"}]},"created_at":"2026-05-25T13:13:30.924Z","updated_at":"2026-05-25T13:13:30.924Z"}