Development and Psychometric Evaluation of the Gambling Treatment Outcome Monitoring System (GAMTOMS)

This article describes the development and initial reliability and validity estimates of the Gambling Treatment Outcome Monitoring System (GAMTOMS), a multi-instrument and multidimensional outcome assessment battery designed to measure gambling treatment outcomes. Reliability methods included both internal consistency of scales and a 1-week test-retest temporal stability procedure. Validity was examined with procedures to estimate content, convergent, discriminant, predictive, and construct validity. Data were collected from 2 separate studies, 1 on the questionnaire version and 1 on the interview version. The questionnaire study included 46 female and 41 male gambling treatment clients and 22 female and 2 male nonclinical participants. The interview study included 88 female and 62 male gambling treatment clients and 16 female and 9 male nonclinical participants. The GAMTOMS was found to yield satisfactory estimates of internal consistency, and 1-week test-retest reliability and was also found to demonstrate satisfactory content, convergent, discriminant, predictive, and construct validity.