Improving the psychometric properties of the problem gambling severity index

This report presents the results of a study that employed advanced statistical techniques to identify the strengths and weaknesses of the PGSI scoring systems and the impact of alternative scoring. Three large population datasets were used: the CPGI integrated dataset which contains CPGI data pooled from the National CPGI validation study and prevalence surveys conducted in Alberta, British Columbia, Ontario (two cycles), Manitoba, Newfoundland between 2001 and 2005; the Canadian Community Health Survey – Mental Health Well-being (CCHS-1.2) which is the 2002 national mental health survey that included the CPGI to assess gambling; and the Leisure, Lifestyle, and Lifecycle Project (LLLP) which is an ongoing (2006-present) longitudinal study of gambling involving adolescents and adults living in rural and urban Alberta. The specific aims of the present study are to (1) assess the validity of the present PGSI severity classifications and cut-off scores for the non-problem gamblers, low-risk, moderate-risk and problem gamblers groups using cross-sectional and longitudinal population data; (2) assess the impact of re-calibrating the PGSI scoring rules on the reliability and external validity of PGSI severity categories; (3) assess the factor structure of the PGSI with newly acquired population data; (4) model the continuum of gambling problems as assessed by the PGSI total score with item response theory (IRT) and identify sources of differential responding across demographic and game type subgroups, and; (5) determine if weights are justified for the PGSI items to recalibrate the scoring and assignment to severity categories.