How Rural is Defined and Why it Matters in Health and Equity Research

“We cannot separate the question of how rural America is
defined from conversations around critical issues like education,
health, racial equity, and economic opportunity in the U.S.”

The Rural Aperture Project
“Defining rural America: The consequences of how we count”

The University of Wisconsin Population Health Institute (PHI) recently released the 2021 Wisconsin Population Health and Equity Report Card. The report measures disparities in health outcomes by race and ethnicity, education levels, and geography in Wisconsin. In reviewing the report, one of PHI’s advisory board members and the executive director of Family Health Center of Marshfield, Inc., Greg Nycz, sparked discussion around how researchers define “rural.”

Measuring health and equity by place along the rural to urban spectrum is an essential part of population health research. Still, there is not one definition for what classifies a community as rural. In fact, the Rural Aperture Project’s, “Defining rural America: The consequences of how we count,” points out that, “There are over a dozen federal definitions of ‘rural’,” and that these definitions often disagree about what places should be considered rural.

Real Case Scenarios: Geography, Dental Carries, and Water Supplies

Greg Nycz has worked for nearly 50 years on access to health care and dental care in rural communities. Through this lens, Nycz shared how unclear definitions of rural impact research findings.

“Let’s say we are researching the dental carries burden in children by geography and are interested in determining if there is a heavier burden in children in rural vs. urban. First researchers must look carefully at the purpose of the research and the different definitions of ‘rural’ that they may choose from for their investigations.”

There are two predominant systems for classifying rural, the U.S. census classification and the Office of Management and Budget’s (OMB) definition. The census classifies rural areas as areas that are not considered urban, and defines urban as areas with population densities of more than 500 people per square mile and places with more than 2,500 people. The OMB defines urban as an area with a central municipality with populations of 50,000 or more, including nearby counties that have strong social and economic links to the central city and surrounding suburbs. Rural is therefore defined as any area that does not fit this definition.

Nycz explained that when looking at dental carriers in rural areas for children, “If a researcher decides to use the census definition of rural, they would look at communities that are very sparsely populated with populations of under 2,500 people. A higher proportion of individuals so classified would typically be using well water, which is not fluoridated.” However, Nycz continued, “Researchers will find a higher proportion of rural people on fluoridated community water supplies if they use the OMB’s definition of rural as nonmetropolitan, which will include small cities of 2,500-50,000 in the sample.”

PHI’s What Works for Health (WWFH) tool assesses the effectiveness of a broad variety of strategies, and these are catalogued in a database for public use. According to WWFH, “There is strong evidence that community water fluoridation (CWF) cost-effectively prevents cavities across socio-economic groups.” Depending on whether the researcher picks the census definition of rural or the OMB definition, they may pull different data for dental health factors, like in this case for fluoridated water.

Distance to medical and dental care services is an important health and equity line of research – but what if researchers see different data depending on the definition of rural?  While OMB’s definition of rural captures levels of connection to larger metropolitan service areas, the census definition does not draw these ties. For example, “When looking at rural places, many of these communities are too small to support medical care practices. The people who live there must travel further for healthcare. Therefore, we find that these communities are more likely to be worse off in terms of access to care and their overall health status,” Nycz shared of a common scenario in which a query about rural health would produce different findings depending on the definition of rural the researcher chooses.

For now, spreading awareness of the different definitions within the research community is an important step forward. “Everything’s complicated,” Greg noted. “That is why we have people dedicating their lives to research to try to untangle some of this stuff. The differences – or lack of differences – we see in the data are based on the choices we make in the definitions we use. The data you explore may limit the definitions you use. For researchers, I recommend looking at multiple definitions and multiple sources of data.”