American Judges Association


Date of this Version



Court Review, Volume 50, Issue 2 (2014)


Copyright American Judges Association. Used by permission.


Scientists typically study variables at the population level, and most of their methodological and statistical tools are designed for this kind of work. The trial process, in contrast, ordinarily concerns whether a particular case is an instance of the general phenomenon. As I have previously observed, “[w]hile science attempts to discover the universals hiding among the particulars, trial courts attempt to discover the particulars hiding among the universals.”1 This essential difference in perspective between what scientists normally do and what the trial process is ordinarily about has yet to be studied with any degree of rigor—by scientists or lawyers.2 Yet this phenomenon is endemic to virtually every context in which law and science meet. Indeed, it might be said to be the single greatest obstacle to the law’s rational use of science.3

The challenges associated with individualizing science, however, are not unique to the law. In fact, in a wide variety of social contexts, empirical research exploring general phenomena are sought to be applied reliably to individual cases. In medicine, for example, research on the effectiveness of various cancer therapies will inform a particular patient’s decision regarding which therapy to choose. In meteorology, research on hurricanes will inform a governor’s decision regarding whether to evacuate a particular city. Indeed, all applied science, ranging from aerodynamics to zoology, potentially presents the problem of making decisions about discrete cases based on group data. Different fields have adapted strategies to respond to the evidentiary-incommensurability challenge with differing degrees of success. In medical decision-making, for example, evidence-based medicine is one way that doctors have sought to bring data to bear on individual diagnostic and therapeutic judgments.4 Meteorologists generate computer models that describe the likelihoods associated with a storm’s path and strength.5 At least from an outsider’s perspective, these efforts have not been so successful that courts would want to borrow them wholesale.6