In this article, the assessment of global pain severity in clinical and health services research is considered. Specifically, the focus is on assessing pain during a defined period by retrospective self-report. Evidence is reviewed that indicates that it can be useful to regard pain severity as a global construct measured by pain intensity and interference with activities. In contrast, pain experience per se is more usefully regarded as multidimensional. Research on methods of assessing key dimensions of pain experience is reviewed, including pain intensity, affect, and chronicity. The authors suggest that global pain severity (made up of pain intensity and interference with activities) and pain persistence (chronicity) should be focal points for brief pain assessment. Two brief measures of pain severity are reviewed that provide practical, reliable, and valid approaches to pain assessment in clinical and health services research.