Spatial Accessibility of Rural Health Care in Colorado Using 2SFCA
Matthew J. Nalty1; Nathan Ryan, PhD2; Benjamin F. Miller, PsyD1; Yash Bhutwala2, Jordan Kovacs2, Alex Robinson & Trung Tran2
1 Eugene S. Farley, Jr. Health Policy Center, Department of Family Medicine, University of Colorado School of Medicine; 2Department of Mathematics, Bucknell University

Introduction
Accessibility to primary and behavioral health careservices is dependent on the patients’ location.
Patients living in rural or frontier locations experiencegreater difficulty in accessing necessary care due tothe number of available clinicians and the distance
between clinic location and the patients home1,2.
Geographic Information Systems (GIS) provides
unique analytical opportunities to evaluate theaccessibility of Primary Care (PCC) and Behavioral
Health (BHC) Clinicians. This study will analyze thespatial accessibility of PCC and BHCs via road
networks in rural Colorado, utilizing a two-step
floating catchment area (2SFCA) along with GIS andpublically available secondary datasets from theCensus Bureau, National Plan and Provider
Enumeration System (NPPES), and the Rural HealthResearch Center.

Methods
1. PCC and BHC locations were geocoded using
custom Python code and the Google Maps API,
then plotted using ArcGIS
2. Two Step Floating Catchment Area method1
used to compute accessibility valuesa. 2SFCA: Fix a provider, compute driving range
b. Find all census block centroids within driving
range
c. Compute driving ranges for each centroid, find allcare providers within union of centroid ranges
d. Score for each provider: take 1 divided bypopulation for each census block, and then takesum for each block in catchment of the providerConclusion

Spatial Accessibility MapsBehavioral Health – 30 min

Increasing the standard drive time to primary andbehavioral health care services from 30 to 90
minutes results in a more uniform distribution of
spatial accessibility scores for those living in ruraland frontier counties in Colorado.

Primary Care – 30 min

Spatial Accessibility
ValuesLimitations

Spatial Accessibility
Values0.000000 - 0.005414

0.000010 - 0.001525

0.005415 - 0.011996

0.001526 - 0.002810

0.011997 - 0.018851

0.002811 - 0.003827

0.018852 - 0.026049

0.003828 - 0.005161

CountiesCounties

Census Tracts

Census Tracts

This emerging research is limited by the data
provided by NPPES which shows an overrepresentation of clinicians who are currently
providing direct patient services. It is further
limited by using the standard 2SFCA method for
spatial analysis.

Next Steps
Behavioral Health – 90 min

Primary Care – 90 min

Spatial Accessibility
ValuesSpatial Accessibility
Values0.000044 - 0.001209

0.000067 - 0.000730

0.001210 - 0.002328

0.000731 - 0.001008

0.002329 - 0.003277

0.001009 - 0.001281

0.003278 - 0.003770

0.001282 - 0.002097

Counties

Counties

Census Tracts

Census Tracts

As we continue this study we will move to use theEnhanced 2SFCA method2, which allows forweighting of counties or census tracts by theirrespective RUC Codes where urban population
centroids will be calculated at the standard 30
minute drive time and rural centroids at 60 or 90
minutes. In addition, Gini indices will becomputed to determine whether or not
healthcare access is equally distributed among
the population. An example of this analysis isdisplayed below for a 30 minute range.

Summary
Typically spatial accessibility to healthcare is measured in 30 minute drive times2. This study’s use of thetwo-step floating catchment area is unique in two ways; 1) to account for real world drive times toservices in rural Colorado we have increased this time to 90 minutes. 2) The 2SFCA method isgenerally applied to primary care accessibility, we have included behavioral health care locations.

References
1.

Vo, A., Plachkinova, M., and Bhaskar, R. (2015) Assessing health care accessibility
algorithms: A compressive investigation of two-step floating catchment methodologies
family. Conference proceedings from Twenty-first Americas conference on information
1. systems, Puerto Rico, 2015.
2. Lou, W., Qi, Y., (2009) An enhanced two-step floating catchment area (E2SFCA) method
for measuring spatial accessibility to primary care physicians. Health & Place. 15, 1100 1107.

Contact: Matthew.Nalty@UCDenver.edu | FarleyHealthPolicyCenter.org