The single item physical activity (SIPA) measure: a major role for global surveillance and community program evaluation

IntroductionPhysical activity is an important global health issue, yet surveillance and measurement methods vary considerably across countries and programs. This paper examines the use of the single-item physical activity (SIPA) measure through a comparative analysis of three representative national surveys and evaluates how well the SIPA reflects national estimates of meeting cutpoints for physical activity guidelines. Finally, we assess the application of the SIPA in the evaluation of four large community-based physical activity programs. MethodsWe describe the SIPA distribution using national data from the Active New Zealand Survey, the Australian National Health Survey and the Irish Sport Monitor. We explore the relationship between the SIPA and existing physical activity measures of guideline attainment using Receiver Operating Characteristic (ROC) analysis, with Area Under the Curve (AUC) as the measure of fit. For the four community programs, we compare pre- to post-program changes, including effect sizes (Cohens {delta}). ResultsAcross the three national datasets, mean SIPA values ranged from 2.68 to 3.31 days/week, with a bimodal distribution--people reported either zero or seven days of physical activity/week. A cutpoint at a threshold of [≥]3 days/week provided optimal classification of guideline attainment (AUC >0.8 in all countries). Across the four large community programs, SIPA values increased by a typical 0.5-1.0 days/week, with 10-30% more participants meeting physical activity guidelines post-program. ConclusionSIPA offers a feasible, low-cost option for both population surveillance and community program evaluation. This is particularly relevant in low-income countries and settings, and complements growing interest in device-based measurement (e.g., accelerometry). Testing of SIPA in low- and middle-income countries is urgently needed. Despite the need for future research, SIPA holds immediate promise as a standardised physical activity measure for policymakers, researchers and community program evaluators. Key MessagesThere are many measures used for physical activity population surveillance and for large program evaluation, but the single item physical activity (SIPA) offers new potential for coordination and standardisation of measures used by asking adults about the number of days/week they were active. Limited research has described population use of the SIPA. This study describes population physical activity levels in national surveys in Australia, New Zealand and Ireland, and also describes the use of the SIPA in the evaluation of physical activity change in four large community physical activity programs. The SIPA provides a validated, comparable, and easy to administer measure for use in physical activity surveillance systems and for policymakers and practitioners evaluating community programs.