His research focuses on studying the relation between the built and natural environment and human behavior, and in particular evaluating the effect of changes to the environment on behavior. One of his interest lies in developing methods to objectively describe behavior and the environment that behavior takes place in. Much of his work builds on intervention studies or natural experiments that involved changes to the built environment, e.g. creating or renovating schoolyards, urban green spaces, public open space, and bicycling facilities. Jasper has published over 80 peer-reviewed articles and numerous reports and popular publications and he is associate editor for the International Journal of Behavioral Nutrition and Physical Activity.