for example if the participant makes a stop at a
bookstore just nearby his/her sport facility after exercising there
in a study of physical activity. In the latter example, the high
degree of spatial accessibility to sport facilities from the bookstore
spuriously reflects that the bookstore itself was reached
from the visited sport facility. As a general rule, valid reference
locations around which to compute accessibility include all the
activity places that would have been visited by the participant
independently of whether the behavior of interest was practiced
or not around them.
Overall, assessing the nature of activities practiced at the