Interpreting prevalence estimates of pathological gambling: Implications for policy

Comparative Test Evaluation: Methods and Challenges

The present paper has three objectives. First, methods for comparing alternative tests for the purpose of replacement of one test with a second presumably superior test are described. Second, problems in the interpretation of the relevance of different diagnostic thresholds (thresholds of positivity) that define who is and who is not a disordered gambler are examined and a potential solution offered in the form of a common quantitative measure of the risk of being a disordered gambler. Third, alternative methodologies are described as potential solutions to the lack of a gold or reference standard in the evaluation of new tests.

The validation of screening tests: meet the new screen same as the old screen?

The focus of this report is to examine the process of validation of new screening tests designed to detect the problem gambler in research and practice settings. A hierarchical or phases of evaluation model is presented as a conceptual framework to describe the basic features of the validation process and its implications for application and interpretation of test results. The report describes a number of threats to validity in the form of sources of unintended bias that when unrecognized may lead to incorrect interpretations of study results and the drawing of incorrect conclusions about the usefulness of the new screening tests. Examples drawn from the gambling literature on problem gambling are used to illustrate some of the more important concepts including spectrum bias and clinical variation in test accuracy. The concept of zones of severity and the bias inherent in selecting criterion thresholds are reviewed. A definition of reference or study gold standard is provided. The use of 2-stage designs to establish validity by efficiently using reference standards to determine indices of accuracy and prevalence is recommended.

Should gambling be included in public health surveillance systems?

This paper examines the question of whether indicators of pathological or disordered gambling should be included in current public health surveillance systems. Such inclusion can be justified in terms of the emerging associations between disordered gambling and the leading indicators of the risk for premature morbidity and mortality. Additional justification can be seen in terms of the potential of Internet gambling to increase the incidence of gambling disorders, particularly among younger and older populations. The paper describes characteristics of public health surveillance systems and recommends including gambling in such systems, on at least a provisional basis.

Student gambling, erroneous cognitions, and awareness of treatment in Scotland

Rates of probable pathological gambling in colleges and universities across Scotland were investigated with a nationally distributed sample consisting of students (n = 1,483) and members of staff (n = 492). Gambling-related erroneous cognitions (Gambling Beliefs Questionnaire [GBQ]) and gambling severity (South Oaks Gambling Screen [SOGS]) were measured, with additional questions enquiring about awareness of treatments available for gambling problems. Rates of past-year problem and probable pathological gambling for students were 4.0% and 3.9%, respectively. An exploratory factor analysis of the GBQ resulted in a 24-item five-factor model, with gambling severity (as indicated by SOGS scores), indices of increasing gambling involvement (gambling frequency and number of gambling activities), and male gender being positively correlated with higher levels of erroneous cognitions, suggesting erroneous cognitions may not be prominent for females with gambling problems. Less than a fifth of students were aware of where to go to receive help for gambling-related problems.

A test of the false positive bias hypothesis

An evaluation of the hypothesis that adolescent gamblers are biased toward the production of false positive responses proposed by Derevensky et al. was tested. The results of secondary analysis of available data supported the hypothesis for items on the South Oaks Gambling Screen and items from the DSM-IV screening instrument. The conclusions were presented as tentative in view of the modest sizes of the observed effects. A number of limitations to the analysis are also described.

The South Oaks Gambling Screen (SOGS): A rebuttal to critics

A review of the literature reveals strong support for the construct validity of interpretations based on scores obtained with the original and more recent versions and/or variants of the South Oaks Gambling Screen (SOGS). Criticisms of the SOGS are shown to lack merit, to be offset by more important criteria, or to be no longer relevant. The evidence reviewed indicates that the construct of pathological gambling as represented by the SOGS and its variants provides a robust definition and implies that the SOGS meets the important criterion of validity generalization. The construct of chasing and behaviors related to chasing is shown to provide powerful measures by which to discriminate between the presence and absence of pathological gambling. The viability of the SOGS to continue to make important contributions to the understanding of pathological gambling is discussed in terms of the criteria for selecting a research instrument.

A comment on the utility of prevalence estimates of pathological gambling

The case is presented that researchers interested in policy aimed at treating the pathological gambler need to shift focus to improving the utility of prevalence estimates. It is argued that researchers supplement prevalence estimates with practical and well-defined measures of severity and other predictors and correlates of help-seeking. The dimension of severity is emphasized as one means of providing estimates that are relevant to policy makers when placed in the context of additional measures that improve their meaning and utility. Estimates may then be partitioned along these dimensions to ascertain the proportion of gamblers most likely to need or seek treatment for gambling-related disorders. The recommendations provided are subject to a number of possible objections and are presented in the interest of stimulating further discussion such as the distinction between symptom assessment and the measurement of severity.

Clarifying the at-risk label: A commentary

The at-risk concept is described and its use in the literature on pathological gambling is discussed. An epidemiologic perspective is proposed and the use of risk, at-risk, and not-at-risk are discussed within this framework. It is shown that within the epidemiologic framework the concept of risk applies to nongamblers as well as gamblers, and some nongamblers are theoretically at risk. An example of the application of risk is provided within the context of smoking and the meaning of risk. The frequent assignment of gamblers with scores of 1 or 2 into the same category as those who score 0 is viewed as problematic and is discussed in terms of true negatives and false negatives and the likelihood of pathological gambling among these gamblers. The need for researchers to identify the determinants and indicators of risk is stressed.