WP 2011-09 An Item Response Theory Analysis of the Problem Gambling Severity Index in a Nationally Representative Sample

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Published in 2012 in Assessment, Volume 19, Issue 2.

ABSTRACT. Increases in the availability of gambling heighten the need for a short screening measure of problem gambling. The Problem Gambling Severity Index is a brief measure that allows for the assessment of social and environmental aspects of gambling with the facility to identify levels of problem gambling. We evaluate the psychometric properties of the PGSI using item response theory methods in a representative sample of the urban adult population in South Africa (N = 3,000). The PGSI items were evaluated for differential item functioning due to language translation. DIF was not detected. The PGSI was found to be unidimensional and use of the nominal categories model provided additional information at higher values of the underlying construct relative to a simpler binary model. This study contributes to the growing literature supporting the PGSI as the screen of choice for assessing gambling problems in the general population.