Criteria for decision-making capacity: between understanding and evidencing a choice

Although the abilities to understand and to evidence a choice are universally recognised as necessary for decision-making capacity (DMC), they are not sufficient for DMC. Additional criteria such as "appreciation", "reasoning", and "using or weighing information" are often used, but the broad and under-defined nature of some of these additional legal criteria has resulted in diverse and sometimes inconsistent interpretations. This article canvasses jurisdictional variations in DMC criteria, focusing on common law and statutory tests in the United States, the United Kingdom and Canada. It proposes a more integrated framework for interpreting DMC beyond the understanding and evidencing a choice criterion by describing how, in addition to the familiar criterion of the ability to form adequate beliefs, "the ability to value" criterion can usefully fill that space. The article illustrates the potential usefulness of this framework by reviewing how the ability to form adequate beliefs and the ability to value are relevant in several challenging cases drawn from the legal literature and clinical experience.