It is crucial to build a strong scientific evidence base, to target and evaluate these new approaches. Understanding the associations (and crucially, causal relationships) between environmental attributes, physical activity behaviors and health outcomes requires careful comparisons of data, within and between countries.

Physical activity habits are determined by multiple levels of influence – personal, family, social, environmental, economic and other factors.

Ecological models of health behavior have been used to synthesize research at these different levels, and to focus attention on relationships of particular physical activities with specific attributes of physical environments, including the built environment.

While physical activity environments will vary within countries, the greatest and most informative sources of variation in the relationships of environmental attributes with physical activity are likely to be between countries.

Thus, the IPEN initiative seeks to stimulate, inform, and support systematic and rigorous studies of physical activity and the environment, in as many countries as possible.

By comparing, for example, the influence on physical activity of people’s exposures to environments as different as those of European city centers, North American suburbs, or small towns and villages in other countries, we can better understand how variations in environmental attributes can promote more-active or inactive behavioral choices.