Invited commentary: rescuing Robinson Crusoe.

Estimating the independent effect of "place" on health outcomes has proven quite difficult. In this issue of the Journal, Auchincloss and Diez Roux contribute a lucid introduction to agent-based simulation models and argue that they may be a fruitful alternative to current approaches to the problem. Insofar as conceptual understanding must precede empirical investigation, this author agrees. Given the obvious shortcoming of pure simulations, the key benefit of agent-based models lies in their ability to alter our thinking and/or theory. Among other things, the approach permits analysts to model (i.e., conceptualize) system dynamics, more realistic social treatment effects, endogenous contexts, and a more congenial image of human behavior.