Improving the psychometric properties of the problem gambling severity index /

Specific issues identified include: the lack validation of for the low-risk and moderate-risk subtypes; the variable range of scores for each of the PGSI- defined subtypes; the limited number of items; choice of wording for the Likert response categories; absence of weights for items; low frequency of endorsement for many items, and; concerns of false positives and false negatives. [...] Present study objectives 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 [...] The percentile ranks provide an indication of how the typical percent of income, monthly expenditures and number of games played in the past year within each group compares to the full distribution of values in the population of Canadian gamblers. [...] We hypothesized that the reliability of the PGSI categories would directly correspond to the range of possible scores, with the non-problem and low-risk gamblers showing the most instability over time. [...] Using the PGSI’s published test- retest reliability coefficient of 0.78, the reliable change index provided a statistical method of determining if the observed change is beyond the limits of chance variation, given the reliability of the assessment instrument.