Because of the importance of pain assessment to understanding the nature and scope of pain problems, and for testing the efficacy of pain treatments, new pain measures are frequently developed. Research that describes the development and evaluation of pain measures should include detailed information concerning the validity and reliability of the measures. However, for the findings from this research to be most useful, the consumers of this research (clinicians and researchers who use pain measures) should understand the concepts of validity and reliability, and the procedures used for evaluating these in pain assessment research. The purpose of this commentary is to provide a summary of these psychometric issues, using the study and findings of Krause and Backonja as an illustrative example of the concepts.