Looking Back and Moving Forward: The Evolution and Potential Opportunities for the Future of Alcohol Outlet Density Measurement.

The literature consistently finds that areas with greater density of alcohol outlets (places that sell alcohol) tend to have higher levels of public health harms. However, conflicting findings arise when researchers drill down to identify the type(s) of alcohol outlets with the strongest associations with harms and the mechanisms that explain these associations. These disagreements could be a result of the outdated methods commonly used to quantify the alcohol environment: counts of the number of outlets in an area. This manuscript reviews the events and ideas that shaped the literature on the physical alcohol environment. It then defines the three main methods used to measure alcohol outlet density, conducts an exploratory factor analysis to explore the constructs underlying each method, and presents a novel conceptual framework that summarizes the three methods, their respective underlying constructs, and the setting(s) in which each may be most appropriate. The framework proposes that counts of alcohol outlets measure availability, proximity to the nearest outlet measures accessibility, and spatial access measures measure access, which comprises both availability and accessibility. We argue that researchers should consider using proximity and spatial access measures when possible and outline how doing so may present opportunities to advance theory and the design and implementation of alcohol outlet zoning regulations. Finally, this manuscript draws on research from other areas of the built environment to suggest opportunities to use novel methods to overcome common hurdles (e.g., separating subtypes of outlets, ecologic designs) and a new challenge on the horizon: home delivery.