The role of consumer perspectives in estimating population need for substance use services: a scoping review

A growing body of research assesses population need for substance use services. However, the extent to which survey research incorporates expert versus consumer perspectives on service need is unknown. We conducted a large, international review to (1) describe extant research on population need for substance use services, and the extent to which it incorporates expert and consumer perspectives on service need, (2) critically assess methodological and measurement approaches used to study consumer-defined need, and (3) examine the potential for existing research that prioritizes consumer perspectives to inform substance use service system planning.

Systematic searches of seven databases identified 1930 peer-reviewed articles addressing population need for substance use services between January 1980 and May 2015. Empirical studies (n = 1887) were categorized according to source(s) of data used to derive population estimates of service need (administrative records, biological samples, qualitative data, and/or quantitative surveys). Quantitative survey studies (n = 1594) were categorized as to whether service need was assessed from an expert and/or consumer perspective; studies employing consumer-defined need measures (n = 217) received further in-depth quantitative coding to describe study designs and measurement strategies.

Almost all survey studies (96%; n = 1534) used diagnostically-oriented measures derived from an expert perspective to assess service need. Of the small number (14%, n = 217) of survey studies that assessed consumer's perspectives, most (77%) measured perceived need for generic services (i.e. 'treatment'), with fewer (42%) examining self-assessed barriers to service use, or informal help-seeking from family and friends (10%). Unstandardized measures were commonly used, and very little research was longitudinal or tested hypotheses. Only one study used a consumer-defined need measure to estimate required service system capacity.

Rhetorical calls for including consumer perspectives in substance use service system planning are belied by the empirical literature, which is dominated by expert-driven approaches to measuring population need. Studies addressing consumer-defined need for substance use services are conceptually underdeveloped, and exhibit methodological and measurement weaknesses. Further scholarship is needed to integrate multidisciplinary perspectives in this literature, and fully realize the promise of incorporating consumer perspectives into substance use service system planning.