AbstractUtility is a quantitative expression of strength of preference. The more something is preferred, the greater is its utility. Formal utility theory for decision making under uncertainty was defined by von Neumann & Morgenstern. Utilities in their theory are measured using the standard gamble. Alternatively, time trade‐off and visual analog scales are used to measure preferences, and these also are sometimes called utilities. Utilities are an integrative measure of health‐related quality of life. Utilities, representing quality of life can be combined with quantity of life to form quality‐adjusted life years. These, in turn, are used in cost–utility analyses. For most clinical studies, the simplest and the preferred way to measure utilities is to use one of the multiattribute health status classification systems that include a utility scoring formula; for example, EuroQol EQ‐5D, Health Utilities Index, or Quality of Well‐Being Scale.
