Evidence, Probability, and the Burden of Proof

47 Pages Posted: 5 Apr 2013 Last revised: 8 Nov 2013

Date Written: November 7, 2013


This Article analyzes the probabilistic and epistemological underpinnings of the burden of proof doctrine. We show that this doctrine is best understood as instructing factfinders to determine which of the parties’ conflicting stories makes most sense in terms of coherence, consilience, causality, and evidential coverage. By applying this method, factfinders should try — and will often succeed — to establish the truth, rather than a statistical surrogate of the truth, while securing the appropriate allocation of the risk of error. Descriptively, we argue that this understanding of the doctrine — the “relative plausibility theory” — corresponds to what our courts actually do. Prescriptively, we argue that the relative-plausibility method is operationally superior to factfinding that relies on mathematical probability. This method aligns with people’s natural reasoning and common sense, avoids paradoxes engendered by mathematical probability, and seamlessly integrates with the rules of substantive law that guide individuals’ primary conduct and determine liabilities and entitlements. We substantiate this claim by juxtaposing the extant doctrine against two recent contributions to evidence theory: Professor Louis Kaplow’s proposal that the burden of proof should be modified to track the statistical distributions of harms and benefits associated with relevant primary activities; and Professor Edward Cheng’s model that calls on factfinders to make their decisions by using numbers instead of words. Specifically, we demonstrate that both models suffer from serious conceptual problems and are not feasible operationally. The extant burden-of–proof doctrine, we conclude, works well and requires no far-reaching reforms.

Keywords: evidence, probability, burden of proof, paradoxes, conjunction, gatecrasher, evidence thresholds, relative plausibility, inference to the best explanation

JEL Classification: K00, K10, K40

Suggested Citation

Allen, Ronald J. and Stein, Alex, Evidence, Probability, and the Burden of Proof (November 7, 2013). Arizona Law Review, Vol. 55, 2013, pp. 557-602, Cardozo Legal Studies Faculty Research Paper No. 388, Northwestern Law & Econ Research Paper No. 13-11, Northwestern Public Law Research Paper No. 13-07, Available at SSRN: https://ssrn.com/abstract=2245304 or http://dx.doi.org/10.2139/ssrn.2245304

Ronald J. Allen

Northwestern University Pritzker School of Law ( email )

375 E. Chicago Ave
Chicago, IL 60611
United States
312-503-8372 (Phone)
312-503-2035 (Fax)

Alex Stein (Contact Author)

Israel Supreme Court ( email )

Sha'arey Mishpat Street

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