Developing a timeline for evaluating public health nutrition policy interventions. What are the outcomes and when should we expect to see them?

OBJECTIVE To develop a timeline for evaluating public health nutrition policy interventions. DESIGN Concept mapping, a stakeholder-driven approach for developing an evaluation framework to estimate the 'time to impact' for policy interventions. The Schools (Health Promotion and Nutrition) (Scotland) Act 2007 was used as the model to develop the evaluation timeline as it had typical characteristics of government policy. Concept mapping requires stakeholders to generate a list of the potential outcomes, sort and rate the outcomes. Multidimensional scaling and hierarchical cluster data analysis were used to develop an anticipated timeline to impact for the policy. SETTING United Kingdom. SUBJECTS One hundred and eleven stakeholders representing nutrition, public health, medicine, education and catering in a range of sectors: research, policy, local government, National Health Service and schools. RESULTS Eighty-five possible outcomes were identified and grouped into thirteen clusters describing higher-level themes (e.g. long-term health, food literacy, economics, behaviour, diet, education). Negative and unintended consequences were anticipated relatively soon after implementation of the policy, whereas positive outcomes (e.g. dietary changes, health benefits) were thought likely to take longer to emerge. Stakeholders responsible for implementing the legislation anticipated that it would take longer to observe changes than those from policy or research. CONCLUSIONS Developing an anticipated timeline provides a realistic framework upon which to base an outcome evaluation for policy interventions and identifies positive and negative outcomes as well as considering possible unintended consequences. It offers benefit to both policy makers and researchers in mapping the progress expected towards long-term health goals and outcomes.