A methodological framework for developing the structure of Public Health economic models

Mathematical models are frequently used to assess the cost-effectiveness of Public Health interventions to improve allocation of scarce resources. Public Health interventions tend to operate within dynamically complex systems and require broader considerations than clinical interventions. Inappropriately simple models and lack of justification may lead to poor validity and credibility, resulting in suboptimal allocation of resources. A conceptual modelling framework is a methodology that guides modellers through the development of a model structure. This research aims to answer the question; ‘What might a conceptual modelling framework for Public Health economic evaluation comprise and what could its potential be to improve model quality?’ Such a framework does not currently exist. The framework was informed by: (a) two literature reviews of the key challenges in Public Health economic modelling and existing conceptual modelling frameworks; (b) qualitative research to understand the experiences of modellers when developing Public Health economic models and their views about using a conceptual modelling framework; and (c) piloting a draft version of the framework within a diabetes prevention project. Evaluation was via theory-based analysis and a focus group of modellers. The conceptual modelling framework comprises four key principles of good practice and a proposed methodology. The principles are; (1) a systems approach to Public Health modelling should be taken; (2) developing a thorough documented understanding of the problem is imperative prior to and alongside developing and justifying the model structure; (3) strong communication with stakeholders and members of the team throughout model development is essential; and (4) a systematic consideration of the determinants of health is central to identifying all key impacts of the interventions within Public Health economic modelling. The conceptual modelling framework is described within the thesis. Evaluation suggested that the framework, which could be used for good practice, reference and education, could improve model quality if disseminated in an accessible form. Future research recommendations include use within different case studies followed by further evaluation and development of methods for modelling individual and social behaviour drawing upon Sociology, Psychology and Public Health.