‘How Much Do You Spend Gambling?’: Ambiguities in Questionnaire Items Assessing Expenditure

Abstract

Expenditure is a dependent variable frequently used in gambling research to index involvement and intensity. However, as a previous study found, self-reported expenditure estimates are ambiguous and imprecise. This paper attempts to (a) replicate the original study, and (b) investigate if specific instructions on methods used to calculate expenditure lead to differences in reported estimates in response to the question, ‘How much money do you spend gambling?’ A total of 637 participants were randomly assigned to one of three groups: Group 1 with no instructions; Groups 2 and 3 with instructions on calculating net and turnover. Results revealed that when heuristics were not specified, half the sample used net expenditure and the remainder used turnover. When heuristics were clearly specified, 30% failed to comply with instructions in calculating estimates. Results undermine the validity of reported gambling expenditure data and support the need for clear instructions on methods used to calculate expenditure.