To address patient’s unmet social needs and improve health outcomes, health systems have developed programs to refer patients in need to social service agencies. However, the capacity to respond to patient referrals varies tremendously across communities. To understand how disparities in spatial access to social service agencies arose we used the National Establishment Time Series (NETS) data set to analyze the density of social service agencies (agencies/Km²), annually, in all populated Census tracts in the U.S. from 1990 to 2014.  Our paper describing this work was published in BMC Health Services Research.

Throughout the period, social service agencies/Km² increased within tracts, with tracts experiencing the highest poverty rates in 1990 having the highest density of agencies through the 1990 to 2014 time-period. But from 1990 to 2014 a spatial mismatch emerged between the availability of social services and the expected need for social services as the population characteristics of neighborhoods changed. Tracts that experienced high poverty in 1990 and then experienced the steepest declines in household income through 2010, had the lowest access to social service agencies in 1990 and the smallest increases in access over the years.  Conversely, high poverty tracts that experienced the largest gains in household income from 1990 to 2010 began the period with the highest density of agencies and gained the most agencies through the study time period.     

We theorize that agglomeration economics benefits and the marketization of welfare may explain the emergence of this spatial mismatch between expected population need for services and the availability of services.  Agglomeration economics posits that there are advantages when similar businesses and institutions locate near one another and near to other physical and commercial resources that will support the mission of these institutions. Agglomerative effects may create centers of gravity that increasingly concentrate service providers in certain neighborhoods through time. The marketization of welfare describes social service providers’ increasing budgetary reliance on fee for service activities. Service providers who partially rely on fee for service activities may be particularly attracted to high poverty areas that are on an upwards economic trajectory and gaining residents who can afford to pay for services.

Agglomeration benefits predict that social services will spatially cluster and further analyzes of our data suggested that clustering of agencies was linked to other elements of urban built form, such as a more robust retail, commercial and institutional environment and access to rail transit. As hospitals and health care systems are increasingly becoming stakeholders in local urban planning, zoning and economic development decisions, they should consider how decisions about urban form may influence spatial access to social services. Hospital system’s advocacy for transit-oriented design and mixed-land use may create the conditions that attract social service agencies into hospital catchment areas. Given the significant role that market forces play in determining the placement of services, attention to interdisciplinary theories across urban planning, economics and social and health services research is needed to improve spatial access to social services.