Evidentiary Policies Through Other Means: The Disparate Impact of “Substantive Law” on the Distribution of Errors Among Racial Groups

This Article develops an analytical framework to investigate novel ways in which legal reforms disguised as “substantive” can affect procedural due process safeguards differently among racial groups. Scholars have long recognized the impact evidence rules have on substantive policies, such as modifying primary incentives or affecting the distribution of legal entitlements in society. However, legal scholars have not paid enough attention to the reverse effect: how changes in “substantive law” influence policy objectives traditionally associated with evidence law—“evidentiary policies.” To fill this gap, this Article discusses three related evidentiary policies. The first is accuracy, which courts and scholars consider a central objective of evidence law. But improving the accuracy of legal fact-finding is not an exclusive function of evidence law. Different substantive rules and doctrines also influence the accuracy of legal decisions. Albeit valuable, accuracy is neither free nor cheap. A second important consideration in evidence law is the cost of litigation—and the cost of fact-finding in particular. Substantive law also plays a role in determining the expense of adjudication. Since we cannot eliminate errors from an adjudicative system with limited resources, we must decide which errors we are willing to accept and which are worthy of spending more resources to avoid. The third example of evidentiary policy affected by substantive law, and the one this Article focuses on, is allocating the risk of mistaken judgments of fact between parties. Standards of proof stand out as a particularly important evidentiary mechanism to distribute the risk of errors. The final error distribution, however, is also a function of other factors, such as the accuracy of the legal fact-finding and how rules are designed and applied. Substantive rules can alter the error distribution in a myriad of ways. Through graphs and other analytical tools, this Article develops a framework to identify and assess these impacts on various situations, including racial disparities between Black and White defendants. The effects of substantive law on allocating error risk between parties raise important concerns for different doctrines, particularly for procedural due process. Courts have consistently held that procedural due process requires an error-distribution strongly biased in favor of criminal defendants. This requirement is primarily enforced through standards of proof and other evidentiary rules. However, this Article argues that substantive law changes can move us away from an errordistribution strongly biased in favor of criminal defendants. Scholars and practitioners often fail to consider these effects when discussing changes to existing laws. This omission comes at a potentially high cost for defendants’ procedural due process and other constitutional safeguards, especially for minority groups.