Policy interventions to improve health through housing: A scoping review.

Despite decades of research documenting the effects of poor housing on health, there is much less evidence of the effectiveness of different housing interventions to improve health outcomes. Moreover, existing research tends to focus on a specific population group or aspect of housing. This scoping review aimed to identify the range of policy instruments and interventions that could improve health by improving housing quality, stability, affordability and availability, with a focus on interventions being implemented in practice, including those not published in the academic literature. For each intervention, we documented aims, effects, actor roles, cost, housing domain, target population, city and country. Based on 37 evidence reviews and reports, we identified 327 unique interventions, with economic and social regulation (e.g., regulating pricing and private rented sector practices, changing planning processes) and direct or contracted provision (e.g., providing and upgrading social housing) much more common than other policy instruments. Evidence on effectiveness varied considerably, with more outcomes reported for physical modifications, economic regulation and tax policy, and limited evidence on social housing, public information, social regulation, effects on health outcomes and measures along multiple stages of a change pathway. Thirty-two types of actors were involved in authorising, financing, implementing and/or enforcing interventions, spanning public and private sectors and levels of government. Intervention costs were infrequently stated and varied substantially, with multiple reviews noting the mismatch between those who finance, implement, benefit and save. This scoping review uncovered more interventions and a wider range of policy instruments than identified in previous systematic reviews, suggesting an important and underutilised role for the grey literature in identifying existing programmes and highlighting evidence gaps. Taking advantage of these natural experiments, embedding more robust evaluation into current interventions and comparing the effectiveness of different policies that aim to achieve similar outcomes offer the opportunity for research to better inform housing policy and maximise its potential to improve health.