Development of a Physical Activity Environment Policy Index (PA-EPI) composite implementation score

Abstract

Abstract Background To promote physical activity (PA), it is necessary to look beyond specific interventions to upstream policies formulated across multiple sectors. The Physical Activity Environment Policy Index (PA-EPI) tool consists of 45 indicators for assessing the extent of policy implementation by national government. Combining measures from different indicators into a single composite measure of policy implementation is complex, but can facilitate cross country policy comparison and communication of policy implementation status to stakeholders. This study describes how a composite measure can be constructed. Methods To create a composite measure two methods were necessary. Firstly, international experts (N = 73, 20 countries) with knowledge of PA policy independently rated the importance of the 45 indicators for increasing population levels of PA on a 10-point Likert scale. A formula was utilised to convert these ratings into weightings for each indicator. Secondly, these weightings were combined with real PA-EPI implementation data. Data from the first study to use the PA-EPI tool, in the Republic of Ireland, was used to demonstrate how a composite implementation score can be calculated. This composite score was expressed as a percentage of a perfect implementation score Results Indicator weightings ranged from 2.7 (highest importance) to 0.8 (lowest importance). Implementation data on indicators ranged from 0.75 to 0.25. The formula used to calculate weightings for each indicator was ωi = (x¯i-∑x¯n)+2. The formula used to derive a composite implementation score was C=∑(ωi×fi) + (ωj×fj)...(ωn×fn). A composite rating implementation score of 59% was calculated for the Republic of Ireland. Conclusions This study demonstrates how data from 45 indicators can be combined. Transnational comparisons are important as they reveal countries at the forefront of PA policy implementation in domains known to be effective for increasing population levels of PA. Key messages • Researchers can use the methods described as part of a process for assessing the extent of implementation of the physical activity policy using the PA-EPI. • By calculating a composite physical activity policy implementation score, researchers can facilitate transnational PA policy comparisons.