Making sense of copious, heterogeneous evidence to inform large-scale public health environmental intervention and policy is highly challenging. This is especially so in complex arenas such as ‘the Food Environment’.
While there is often sufficient evidence of associations between risk factors and environmental determinants, few food environmental and policy actions have been implemented and/or sufficiently evaluated to provide robust evidence of effectiveness at the impact and outcome levels. Linking intervention to distal health outcomes of policy interest, such as obesity, is often not possible.
Additionally, study designs applicable to the clinical setting are often much less applicable or possible in public health. Further, decision-makers can lack an understanding of the different types of evidence that might inform decision-making in these more complex areas hence may dismiss evidence considered less ‘strong’ according to traditional evidence hierarchies. Systematic reviews of randomised, controlled ‘trials’ are still hailed as the gold standard despite them rarely providing answers to broad public health policy questions.
The lack of consensus on an evidence grading system within the public health domain further stymies the synthesis and translation of evidence. Existing schemas and typologies differ in the criteria used to appraise individual studies and to grade overall bodies of evidence. They differ also in the text descriptors used for communicating the ‘strength’ of evidence.
In this presentation I describe the challenges encountered in synthesising, appraising and communicating the complex, diverse evidence base with respect to the retail, pricing and promotion domains of the food environment, to inform government decision-making. An extensive dialogue between the reviewer and government was required to find solutions to these challenges. The tabulated summaries of evidence will be presented and discussed to illustrate the identified solutions in this instance.