Physical Referral Networks by State
This dashboard aggregates information about the Hospital Service Areas (HSAs) in each state of the United States. There are four main sections: Referral Network Features, Demographic Data, Patient Outcomes, and Pricing & Payments. Each section contains multiple metrics that provide insight into the healthcare systems in the selected state. Select the state of your choice and click "Apply" to populate the dashboard.
Referral Network Features
from referral_network_features
This section contains information about the structure of the HSA's referral network. For more information about how referral networks are formulated, see Characterizing Physician Referral Networks with Ricci Curvature, by Jeremy Wayland, Russel J. Funk, and Bastian Rieck (2024).
These features provide insight into the connectivity and efficiency of the healthcare system in each area.
Hover over each graph to see the exact distribution of values for each year.
Number of Providers per HSA:
The number of nodes in the HSA referral networks (i.e. the number of providers in each HSA), a proxy for HSA size. This varies dramatically between HSAs, the smallest having only two providers and the largest having over 7,000 providers (New York City).
Mutual Care Index (MCI):
Values range from 0 to 1, with higher values indicating a higher proportion of mutually shared patients between providers in the network. The 2017 average among all HSAs was 0.69, with a standard deviation of 0.19.
In other words, if Provider A shares patients with Providers B and C, the chance that Providers B and C also share patients is the MCI * 100. For each HSA, this is calculated by taking the average clustering coefficient across physicians (i.e., average_clustering).
Care Convergence Index (CCI):
Positive CCI values indicate high connectivity and efficient flow through the system. Conversely, negative values indicate the presence of bottlenecks and inefficient movement through the system. For each HSA, the CCI is calculated by taking the average Forman curvature of the network (i.e., forman_mean).
The 2017 average among all HSAs was -9.36, with a standard deviation of 30.89.
Demographic Data from the US Census
from population_census
The US Census provides valuable information about an area's population, helping to contextualize the healthcare systems and the people they serve. We are concerned with identifying disparities in the quality and accessibilty of healthcare, with particular attention to those who have been historically marginalized.
Demographic data is retrieved via the zip code associated with each HSA.
We report the distribution of the following socioeconomic and demographic metrics across HSAs in this state.
Median Household Income:
The median household income in the HSA, a measure of the relative affluence of the area.
Unemployment Rate:
The percentage of the population that is unemployed, a measure of the state of the local economy.
Percentage of Population without a High School Degree:
The percentage of the eligible population that does not have a high school degree, a measure of the local education system.
Percentage of Population Identifying as Black:
The percentage of the population that identifies as Black or African American.
Percentage of Population Identifying as Hispanic:
The percentage of the population that identifies as Hispanic.
Patient Outcomes (Post Discharge)
This section contains information about the patient outcomes in the post-discharge period. This data lends insight into the effectiveness of care and patient transitions from hospital to home.
For more information on data collection and how expected rate is calculated, see the Dartmouth Atlas of Health Care.
For both medical and surgical hospital admissions (top and bottom row, respectively), we report the following post-discharge metrics.
Readmission Rate:
The percent of patients readmitted within 30 days of discharge following medical/surgical admission.
Observed vs. Expected Readmission Rate:
The ratio of the observed vs. expected values for the percent of patients readmitted within 30 days of discharge following medical/surgical admission. Values greater than 1 indicate higher than expected readmission rates, while values less than 1 indicate lower than expected readmission rates.
ER Follow-Up Rate:
The percent of patients who follow up with an ER visit within 30 days of discharge following medical/surgical admission.
Observed vs. Expected ER Follow-Up Rate:
The ratio of the observed vs. expected values for the percent of patients who follow up with an ER visit within 30 days of discharge following medical/surgical admission. Values greater than 1 indicate higher than expected ER follow-up rates, while values less than 1 indicate lower than expected ER follow-up rates.
Standard Pricing and Payments
from standard_pricing
This section tackles pricing - a crucial aspect of healthcare accessibility. We report Medicare payments for various medical services, lending insight into the cost of care in different regions and how it may impact patient access.
Medicare payments are adjusted to the area to account for regional price differences, but are standardized here for ease of comparison.
For more information on how Medicare payments vary across different regions and the price-standardization methods used by the Dartmouth Atlas of Health Care, see their technical report.
We offer the following metrics regarding the price of healthcare services.
Physician Visit Reimbursements per Enrollee (Price-Adjusted):
This is the dollar amount per enrollee reimbursed by Medicare for physician visits, price-adjusted for the area.
Hospital Reimbursements per Enrollee (Price-Adjusted):
This is the dollar amount per enrollee reimbursed by Medicare for care at hospital and skilled nursing facilities (SNFs), price-adjusted for the area.
Medical Equipment Reimbursements per Enrollee (Price-Adjusted):
This is the dollar amount per enrollee reimbursed by Medicare for durable medical equipment (DME), price-adjusted for the area.
Total Reimbursements per Enrollee (Price-Adjusted):
This is the total dollar amount per enrollee reimbursed by Medicare, price-adjusted for the area.
Observed vs. Expected Values:
Below each of these metrics is the ratio of the observed price-adjusted reimbursement amounts (recorded in the metrics above) vs. the expected price-adjusted reimbursement amounts. Values greater than 1 indicate higher than expected Medicare reimbursements, while values less than 1 indicate lower than expected reimbursements.
More information on how expected reimbursement rates are calculated can be found in the Dartmouth Atlas of Health Care.