San Diego Law Review


Gustavo Ribeiro

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Document Type



This Article defends a system with a greater variation in the number of standards of proof than we currently have as both normatively and descriptively valuable. Standards of proof are mechanisms for allocating the risk of factual error between parties. For example, the heightened “beyond a reasonable doubt” standard in criminal cases reflects an aspiration for a legal system erring more in favor of mistaken acquittals than mistaken convictions. Surprisingly, we then assign the same standard to very different cases under the justification that we accept, or should accept, the same error-distribution for those cases. This Article argues that, however ubiquitous, this justification is twice mistaken. First, it is normatively mistaken. There are important arguments in support of a system with varying standards of proof based on welfare, fairness, and distributional considerations. Second, this justification is also positively mistaken. Decades of behavioral psychology research on jury decision-making suggests that jurors do not make decisions based on the same error-distribution for all cases. This Article also replies to objections against my proposal, two of which stand out. According to some scholars, for my proposal to work we would need a lot of empirical information which is difficult to obtain. This Article argues that, while we wait for the data, we should understand standards as sub-optimal generalizations, with concrete results that might be hard to verify. Another important objection is that we already adjust the error-distribution with other legal mechanisms, such as by adding or removing causes of action. Even if that is true, this Article shows how such strategy is inferior to my proposal. All these considerations push in the direction of a greater variation in the number of standards. Profound policy consequences follow. Society becomes hard-pressed to reevaluate the socially optimal error-distributions on different types of cases and what should be the corresponding standards of proof.