Quantitative health impact assessment methodology for societal initiatives: A scoping review

Health initiatives are increasingly situated outside the institutionalised public health sector. The intersectoral character of societal initiatives, along with indirect relationships between initiatives and health, makes making projections of reach, impact and goal achievement complex. This scoping review of the peer-reviewed literature searches for appropriate methods to conduct quantitative health impact assessment for such initiatives. Database searches were done in PubMed and Web of Science, as well as a reference list search. Studies were then selected in a systematic manner. The review includes 64 studies. Most studies made estimates using simulation methods, notably with Monte Carlo, Markov and system dynamics modelling. Inputs for the models such as transition probabilities and price elasticities were taken from census, register and survey data, evidence from previous (scientific) studies and sometimes outcomes from stakeholder participation. Of different health outcome measures, the number of deaths was most frequently used, followed by QALYs and DALYs and life years. Health effect distribution is frequently mentioned, but not often estimated. Scientific methodological publications on HIAs focusing on civil society initiatives are relatively sparse, indicating possibilities for further methodological advancement. Estimating health effect distributions and incorporating stakeholder participation could make meaningful additions to standard practice.