Population prevalence surveys of gambling serve several important purposes. However, there has been some question about the accuracy of the prevalence rates obtained in these surveys. These questions concern whether non-gamblers are under-represented in ‘gambling’ surveys due to lack of interest/participation; whether different administration formats (telephone; face-to-face) produce equivalent results; the true status of the many instrument-identified problem gamblers who do not report any corroborating gambling behaviour; and the weak correspondence between problem gamblers identified in population surveys and their subsequent assessment in clinical interviews. The need to resolve some of these issues motivated the present authors to embark on a program of research designed to bring clarity to the true rates of problem gambling and to help identify ‘best practices’ in the population assessment of gambling and problem gambling.