Access or adaptation? A meta-analysis of surveys of problem gambling prevalence in Australia and New Zealand with respect to concentration of electronic gaming machines

It is widely believed that greater availability of electronic gaming machines (EGMs) has led to increases in problem gambling prevalence and related harms. It has also been proposed that individuals and populations adapt to exposure over time and that prevalence rates plateau or decline, even in the face of increasing availability. This study examines both hypotheses using a combined data set of 34 problem gambling surveys conducted in Australia and New Zealand since 1991. Strong statistically meaningful relationships were found for an increase in prevalence with increasing per capita density of EGMs, consistent with the access hypothesis and supported by no evidence of plateauing of prevalence with increasing density of EGMs. A decrease in prevalence over time with availability held constant is also evident, partially consistent with adaptation. It is likely that both forces are at work simultaneously, with implications for appropriate policy responses to gambling harm minimisation.