Particularly in this time of high interest rates and high housing costs, real estate agents are likely to rely on a classic aphorism: "Location, location, location. " This recognizes that the location of a dwelling is a major determinant of its desirability and cost due to its immutable nature. In addition to the association of a home's location with its monetary cost, though, what additional role may it play in the lives of those who inhabit it? A growing number of reports describe the association of social determinants of health, including those linked to location, to both acute and critical illness in children.These social determinants of health, whether considered on an individual basis or through multidimensional measurement, are associated with healthcare utilization, illness severity, length of stay, and rehospitalization in both individual disease states as well as broader patient populations (1-7). Although pediatric intensivists have not traditionally considered prevention of critical illness as a focus of our profession, these data make it clear that our patients are not isolated from the impact of inequities on disease prevalence and outcomes. The doors to the ICU do not shut out the influences of the environments where our patients learn, play, and live. Unfortunately, this includes the effects of a long history of discriminatory practices, including segregation and redlining, on health outcomes.In this issue of Pediatric Critical Care Medicine, McCrory et al (8) further our understanding of these effects. They describe the association between census tract-level social determinants of health and outcomes of critical illness in a multi-institutional retrospective cohort study of nearly 34,000 patients. Much like in real estate, the specific way location is described may influence associations with variables of interest. While an enterprising real estate agent may advertise a "trendy" neighborhood location for a housing unit, health services researchers (and consumers of their work) must be mindful of how an individual patient address is characterized. A significant strength of this article involves the use of census tract data in place of postal codes. ZIP codes were first introduced by the U.S. Postal Service in the 1960s with the goal of optimizing mail delivery. They correspond to address groups and delivery routes and are not intended to be static over time or uniform in geographic size (9). Nevertheless, because ZIP codes fit in the mental model of "place" and are easily accessible in administrative data, they have become a common geographic unit by which social determinants of health are measured and reported in the United States.Census tracts, unlike ZIP codes, are specifically designed to correspond with neighborhood boundaries and are standardized over time. However, they are typically unavailable in administrative data such as the Pediatric Health Information System, the Healthcare Cost and Utilization Project, or, as in the study by McCrory et al (8), the Virtual Pediatric Systems databases...
