1. Collaboration between health economic modellers & behavioural/ social scientists 

Collaboration is about working together towards a shared goal to produce better outcomes than could be achieved individually. There would be a benefit to greater collaboration between behavioural and social scientists and health economic modellers in a cyclical process of intervention development and evaluation (Meier et al., 2019; Bates et al., 2022). This would align with the latest guidance for developing and evaluating complex interventions (Skivington et al., 2021). Collaboration could enable better understanding by health economic modellers and behavioural scientists about which elements of their research are important for achieving shared goals and how they can inform each other. Early health economic model development/ input may lead to the conclusion that it is not worthwhile to study the effectiveness of a public health intervention, or it could inform useful data collection for evaluation. Psychologists, sociologists and/ or behavioural economists could help modellers to understand the evidence, the behavioural theory used to develop interventions, and to help inform assumptions beyond study follow up where no data exist.

The APEASE criteria has been developed for assessing interventions at any stage of development or evaluation (West et al., 2019; Michie et al., 2014; Brierley et al., 2022). This comprises Acceptability, Practicability, Effectiveness (and cost-effectiveness), Affordability, Spill-over effects, and Equity, and if any of these are not deemed by stakeholders to be met then the intervention should not be considered. Throughout this paper, stakeholders include members of the public affected by the interventions, people delivering the interventions and commissioners of the interventions. The APEASE criteria could be used to develop shared goals for collaboration. Within a health economic model, Effectiveness, Affordability, Side-effects and Equity can be explored, whilst it would not be worthwhile assessing interventions within a health economic model if they were not considered to be acceptable or practical by stakeholders.