Challenges in targeting areas for public action. Target areas at the right place and at the right time

While some public interventions are implemented across a whole country and concern everyone, many public interventions focus only on a segment of the population (priority groups) or a part of the territory (priority areas). Targeting groups (ie, children, elderly people, pregnant women, smokers, migrants, etc.) has long been a strategy to reduce social and health issues. Recently, targeting areas has emerged as an attractive way to implement public action. However, area-based interventions raise significant challenges for policy-makers, especially when they want to kill two birds with one stone by combining two targets: priority groups (ie, for whom health issues are frequent) and priority areas (ie, for whose attributes impacting health outcomes gain to be modified).