Calculating access to parks and other polygonal resources: A description of open-source methodologies.

Public health studies routinely use simplistic methods to calculate proximity-based "access" to greenspace, such as by measuring distances to the geographic centroids of parks or, less frequently, to the perimeter of the park area. Although computationally efficient, these approaches oversimplify exposure measurement because parks often have specific entrance points. In this tutorial paper, we describe how researchers can instead calculate more-accurate access measures using freely available open-source methods. Specifically, we demonstrate processes for calculating "service areas" representing street-network-based buffers of access to parks within set distances and mode of transportation (e.g., 1-km walk or 20-minute drive) using OpenRouteService and QGIS software. We also introduce an advanced method involving the identification of trailheads or parking lots with OpenStreetMap data and show how large parks particularly benefit from this approach. These methods can be used globally and are applicable to analyses of a wide range of studies investigating proximity access to resources.

Improving our estimates: assessing misclassification of abortion accessibility in the United States.

PURPOSE: Quantify the misclassification of abortion accessibility resulting from calculations based on block groups, census tracts, ZCTAs, or counties versus census blocks. METHODS: We included 850 facilities from the 2018 ANSIRH Facility Database and Planned Parenthood website. Accessibility was the proportions of 18-44 year-old women living within a 30-, 60-, and 90-minute drive from an abortion-providing facility. We calculated accessibility using five different geographic units: census blocks, block groups, census tracts, ZCTAs, and counties. We estimated the potential magnitude of abortion accessibility misclassification resulting by calculating the difference between accessibility calculated using each geographic unit, respectively, for each drive time as compared to census blocks. RESULTS: In this analysis, counties, the largest geographic unit considered, underestimated national abortion accessibility compared with census blocks by up to 24.21 percentage points; while block group-, census tract, or ZCTA-based national estimates of abortion accessibility in the US resulted in small underestimates relative to estimates constructed using census blocks. CONCLUSIONS: Studies of population accessibility should use the smallest feasible geographic unit of analysis. While this study focused on abortion accessibility, our findings likely apply to other health services, particularly those with distributions like abortion care.

Potential Impact of Telemedicine for Medication Abortion Policy and Programming Changes on Abortion Accessibility in the United States.

Objectives. To quantify the impact of telemedicine for medication abortion (TMAB) expansion or ban removal on abortion accessibility. Methods. We included 1091 facilities from the 2018 Advancing New Standards in Reproductive Health facility database and Planned Parenthood Web site, among which 241 did not offer abortion as sites for TMAB expansion. Accessibility was defined as the proportion of reproductive-aged women living within a 30-, 60-, or 90-minute drive time from an abortion-providing facility. We calculated accessibility differences between 3 scenarios: (1) facilities offering abortion in 2018 (reference), (2) the reference scenario in addition to all facilities in states without TMAB bans (TMAB expansion), and (3) all facilities (TMAB ban removal). We also stratified by state and urban-rural status. Results. In 2018, 65%, 81%, and 89% of women lived within a 30-, 60-, or 90-minute drive time from an abortion-providing facility, respectively. Expansion and ban removal expanded abortion accessibility relative to the current accessibility scenario (range: 1.25-5.66 percentage points). Women in rural blocks experienced greater increases in accessibility than those in urban blocks. Conclusions. TMAB program and policy changes could expand abortion accessibility to an additional 3.5 million reproductive-aged women. Public Health Implications. Our findings can inform where to invest resources to improve abortion accessibility. (Am J Public Health. 2022;112(8):1202-1211. https://doi.org/10.2105/AJPH.2022.306876).