Reliability and validity of the SF-12v2 in the medical expenditure panel survey

Evaluate the reliability and validity of the Medical Outcomes Study Short-Form version 2 (SF-12v2) in the 2003-2004 Medical Expenditure Panel Survey (MEPS). Data were collected in the self-administered mail-out questionnaire and face-to-face interviews of the MEPS (n = 20,661). Internal consistency and test-retest reliability and construct, discriminate, predictive and concurrent validity were tested. The EQ-5D, perceived health and mental health questions were used to test construct and discriminate validity. Self-reported work, physical and cognitive limits tested predictive validity and number of chronic conditions assessed concurrent validity. Both Mental Component Summary Scores (MCS) and Physical Component Summary Scores (PCS) were shown to have high internal consistency reliability (alpha > .80). PCS showed high test-retest reliability (ICC = .78) while MCS demonstrated moderate reliability (ICC = .60). PCS had high convergent validity for EQ-5D items (except self-care) and physical health status (r > .56). MCS demonstrated moderate convergent validity on EQ-5D and mental health items (r > .38). PCS distinguish between groups with different physical and work limitations. Similarly, MCS distinguished between groups with and without cognitive limitations. The MCS and PCS showed perfect dose response when variations in scores were examined by participant's chronic condition status. Both component scores showed adequate reliability and validity with the 2003-2004 MEPS and should be suitable for use in a variety of proposes within this database.