Environment and Physical Activity Dynamics: The Role of Residential Self-selection

OBJECTIVES: Within the socio-ecologic framework, diet and physical activity are influenced by individual, interpersonal, organizational, community, and public policy factors. A basic principle underlying this framework is that environments can influence an individual's behavior. However, in the vast majority of cross-sectional and even the few longitudinal studies of this relationship, the question of whether individuals select their area of residence based on physical activity-related amenities is ignored. In this paper, we address a critical methodological issue: self-selection of residential location, which is generally not accounted for, and can significantly compromise research on the relationship between environmental factors and physical activity behaviors. METHOD: We define and discuss the problem of residential self-selection in the study of neighborhood influences on health and health behavior, review methods used to control for residential self-selection in the literature, and present our strategy for addressing this potentially important source of bias. CONCLUSION: Existing research has built our understanding of residential self-selection bias, but important gaps remain. Our strategy uses data from a longitudinal cohort study linked to contemporaneous environmental measures to create a multi-equation model system to simultaneously estimate residential choice, environmental influences on physical activity, and downstream health outcomes such as obesity and clinical cardiovascular disease risk factor measures.     

Responses of normal and learning disabled children as a function of the stopwatch in the matching familiar figures testing situation

To ascertain whether normal and hyperactive learning disabled children differ in their responses to Kagan's Matching Familiar Figures Test (MFF) as a function of a temporal cue, the stopwatch used in the testing situation, 16 learning disabled and 15 normal 8- and 9-year-old boys were compared. A counterbalanced design, in which each child was administered one-half of the test with a stopwatch (standard administration procedure) and the other one-half of the test without a stopwatch (No-Stopwatch procedure), was used. For the normal children, the MFF latency scores in the two conditions were not correlated, indicating that the stopwatch influenced their performance. For the learning disabled children, however, the MFF latency scores in the two conditions were correlated. A significant difference between the two correlation coefficients indicated that the normal and learning disabled children responded in a different manner to the temporal cue. On the MFF error measure, the correlation between the scores obtained in the two conditions of test administration was significant for the normal children, but not for the learning disabled children. A significant difference between these correlation coefficients again indicated differential responding to the temporal cue by the two groups.