The 10-item and 20-item gambling harms scale for affected others (GHS-10-AO, GHS-20-AO): benchmarked to health utility using propensity weighting and control for comorbidities

Gambling-related harms significantly impact not only gamblers but also people socially connected to them (affected others or AOs), yet quantifying these impacts has remained challenging. This study developed and validated two scales for measuring harm to people due to someone else’s gambling − the 10-item and 20-item Gambling Harms Scale for Affected Others (GHS-10-AO and GHS-20-AO) − benchmarked to health utility metrics. Using data from 2,018 Australian adults with close relationships to gamblers, we employed psychometric item selection, propensity weighting, and control for comorbidities to establish evidence for causal links between reported harms and health utility decrements measured by the SF-6D. Emotional, relational, and financial harms were the most prevalent items selected. Both scales demonstrated excellent reliability (α = 0.89 for GHS-10-AO; α = 0.94 for GHS-20-AO) and strong correlations with health utility measures (r = -0.47 to −0.48 with SF-6D). The relationship between harm scores and health utility showed significant non-linearity, with increasing convexity at higher harm levels. These scales provide the first validated instruments for quantifying health impacts to AOs using a common metric comparable to gambler-focused harm measures, enabling population-level assessment of current gambling harm in the adult population; inclusive of gamblers and connected others. The instruments fill a critical gap in gambling harm measurement and offer jurisdictions tools for monitoring progress toward harm minimisation that encompasses impacts on both gamblers and those around them.