Factors influencing use and choice of Core Outcome Sets and outcome measurement instruments in trials of interventions to prevent childhood obesity: A survey protocol

Background Two core outcome sets for childhood obesity prevention have been developed; standardised sets of outcome measurement instruments for these core outcome sets are currently being developed. Core outcome sets and standardised measurement sets can reduce heterogeneity and improve evidence syntheses for trials of interventions to prevent childhood obesity and/or interventions to improve child health behaviours related to childhood obesity. Such benefits are only realised if core outcome sets and standardised measurement sets are used in trials. The aims of this study are 1) to examine trialists’ awareness and attitudes towards the two existing core outcome sets and factors influencing their use; 2) to explore the characteristics of outcome measurement instruments that trialists currently use; and 3) to better understand how trialists choose outcome measurement instruments and the factors that influence those choices. Methods A cross-sectional online survey will be conducted with researchers involved in the design and/or conduct of trials of interventions to prevent childhood obesity and/or to improve child health behaviours related to childhood obesity, in children aged 0 to 5 years (trialists). Trialists will be recruited using purposive sampling, and will complete a 22-item survey examining trialist characteristics, awareness of the existing core outcome sets, factors influencing use of the existing core outcome sets, characteristics of measurement instruments, how trialists choose measurement instruments, and factors influencing choice of measurement instrument. Quantitative data will be analysed descriptively; responses to open-ended questions will be analysed using qualitative content analysis. Conclusions Findings from this study will inform approaches to maximising use of core outcome sets and standardised measurement sets for childhood obesity prevention. Use of standardised approaches to what and how outcomes are measured in this area will reduce heterogeneity and research waste and enhance evidence syntheses to better determine intervention effects.