Appendix: Detailed Methodology and Data Sources

Detailed methodology and data sources

This page covers the methodology and data sources for two primers:

• Emergency Medical Services (EMS): Local Authority, EMS Funding, Organization, and Management
• Emergency Medical Services (EMS): A Look at Disparities in Funding and Outcomes

These primers include data gathered from several sources. First, a detailed review of the literature was conducted. In January 2022, a Centers for Disease Control and Prevention (CDC) library search of PubMed and Scopus was completed to gather relevant evidence published between January 18, 2012, and January 18, 2022. The research team identified 116 items using the following search terms:

• PubMed ("Emergency Medical Services/Economics"[Mesh] OR "Emergency Medical Services/Legislation and Jurisprudence"[Mesh] OR "Emergency Medical Services/Organization and Administration"[Mesh]) AND "Cardiovascular Diseases"[Mesh] AND "California"[Mesh] AND ("Healthcare Disparities"[Mesh] OR "Health Status Disparities"[Mesh] OR "Minority Health"[Mesh]) - 2012+, Eng

• Scopus (Emergency AND ("Medical Services" OR Department OR Room)) AND (Fund* OR Regulation OR Polic* OR Authority) AND ((Cardiovascular OR Cerebrovascular OR Atherosclerotic) AND Disease) OR ("Heart Disease*" OR Stroke OR "Heart Failure" OR Hypertension OR "Blood Pressure" OR "Hyperlipidemias" OR "High Cholesterol" OR dyslipidemias OR "Atrial Fibrillation" OR "Cardiovascular Event*" OR "Myocardial Infarction" OR "Heart Attack") AND California AND Disparit* - 2012+, Eng

The research team excluded 79 items because of duplication, non-U.S. setting, and/or lack of relevance to the research topic (i.e., CVD and EMS). The remaining 37 items were used in developing the primers.

To compile local laws, Municode and local government websites were used. In this cross-sectional analysis, the research team reviewed laws that were in place in May of 2022 when the search was completed. For legal analysis, laws related to local government revenue sources (particularly property and sales taxes), laws covering special districts related to EMS and fire, and laws authorizing local governments to provide and regulate EMS were compiled. After a detailed search protocol was developed, the laws were downloaded and coded. Each law was independently coded by two separate coders, who then compared codes and reconciled any differences. Using Westlaw, two independent coders similarly downloaded, coded, and reconciled state laws related to taxation, special districts, and local government autonomy. This facilitated an examination of the degree of local autonomy provided by the state government and comparison of the degree to which the various counties take advantage of that autonomy. Financial autonomy was the primary focus in efforts to ascertain the degree to which local governments can fund EMS.

Researchers also completed an in-depth examination of local government revenues and funding sources for EMS. This information was gathered from the annual plans of local EMS agencies (LEMSAs) published on the California EMS Authority website. Annual revenues and expenditures were collected for all recent years reported by the LEMSAs, and any discrepancies were noted. The research team started with the pre-assigned revenue and expenditure categories suggested by the EMS agency template and used by the LEMSAs, and then consolidated into categories by level of government.

Because large year-to-year financial fluctuations were observed in both revenues and expenditures in many LEMSAs, data were aggregated for all available recent years, and a simple average of these years was taken. Per capita figures were calculated via the county/counties populations for each year used in the financial reports, as based on U.S. Census Bureau county-level population data from 2021 (the latest available year).

Revenue data were not adjusted for inflation for a variety of reasons, principally because there does not seem to be an appropriate index for these data. The U.S. Bureau of Labor Statistics' Consumer Price Index's medical care price index is not appropriate, because it uses the prices that consumers face, not local governments (which in this case are producers), and EMS are not included in the index.1 The costs of inputs to produce EMS are principally the labor of emergency medical technicians and related staff and the costs of owning and running ambulances and similar vehicles provided through fire departments. The cost of labor varies enormously across California, from volunteer services in rural communities to highly trained professionals in competitive markets in metropolitan areas. Indices are available for the three largest metropolitan areas in California (Los Angeles, San Diego, and San Francisco); it is notable that the average level of spending per consumer is more than $1,000 higher (or nearly 30% more) in San Francisco than in Los Angeles. Differences between these areas and rural communities in terms of spending and prices will almost certainly be larger.2 The separate indices for metropolitan areas give no indication of trends for rural areas. The revenues and expenditures are typically historically driven in that they vary little from year to year, barring changes to revenue availability, and are not driven by short-term costs. So they are not a relevant indicator of the level of services provided. Similarly, prices and costs are not covered in the U.S. Bureau of Labor Statistics' Producer Price Index.3 The California Department of Industrial Relations produces price indices for four separate urban areas in California: Los Angeles, focused on Los Angeles County; San Diego; San Francisco; and the Riverside-San Bernadino area (other areas of Los Angeles).4

The spending per person was calculated by finding expenditures in public EMS reports and dividing that number by the population of the county or counties, using Census Bureau data as described above.

Data on state and federal funding for EMS Offices came from the National EMS Assessment performed by the National Association of State EMS Officials (NASEMSO). Per capita figures were calculated using Census Bureau data. The NASEMSO report indicates that most state EMS offices submitted data between April and December of 2019, so it is assumed that the budget figures refer to the 2018 year. To calculate per capita funding for each state, the total state and federal funding figures were divided by the Census Bureau's state population estimate on July 1, 2018.

Quality indicator data for each LEMSA were referenced from the California EMS Authority's EMS Core Quality Measures Project. The project aims to increase the availability and accuracy of pre-hospital data for public, policy, academic, and research use and to foster EMS evaluation and improvement through grants provided by the CHCF.5 Data were collected from the 2019 quality indicators report. In addition to the reported data for the five LEMSAs studied, data for all LEMSAs' indicators were gathered, and used to calculate whether any fell within the highest or lowest quintile of LEMSAs reporting their quality indicators. Quintiles are calculated by rank ordering reported performances from high to low (in the range of 100% to 0%), and calculating cutoffs for scores that put a LEMSA in the highest 20% of those reporting, or the lowest 20% of LEMSAs reporting. This method weights the observations of each LEMSA equally. Examining quintiles in the evaluation of data is a common practice in the literature.67