Determinants of Geographic Variation in Public Health Preparedness: System Structure and Risk Exposure

OBJECTIVES: A growing body of evidence nationally documents wide variation in public health capacities across local areas, suggesting gaps in quality, efficiency, and interoperability as well as inequities in risk protection. Volume-outcome relationships may explain some of this variation if agencies realize economies of scale in performing public health activities and/or if they learn from experience in responding to relatively rare events. This study (1) estimates the magnitude of variation in public health preparedness capacities across U.S. communities; and (2) investigates how an agency's scale of operations and its frequency of exposure to emergencies affect local preparedness capacities. STUDY DESIGN: We used a national, cross-sectional survey of local health departments conducted during summer and fall 2010. We developed and validated a self-administered survey to measure agency capacities to prepare for and respond to public health emergencies from an all-hazards perspective. Multivariate hierarchical models were used to isolate the effects of agency scale and experience on composite measures of preparedness. FINDINGS: Composite measures of preparedness varied by a factor of 1.8 to 2.9 between the highest 20% and lowest 20% of agencies when ranked on capacity scores, with most of this variation persisting after adjusting for state-level fixed effects. Multivariate estimates indicated positive returns to scale in all eight domains ranging from 4.6% to 13.5% improvements in preparedness scores for each 10% increase in population size (p<0.05). Estimated returns to experience were statistically significant in four domains, ranging from 0.4% to 4.7% improvements for each 10% growth in declared events. CONCLUSIONS: Local capacity to respond to public health emergencies varies widely across U.S. communities and appears highly responsive to an agency's scale of operations and the volume of events experienced. Efforts to pool public health operations and experience through regionalization, consolidation, and strategic alliances may strengthen public health capacities significantly.