The following description is provided by the Census:

Research has suggested that people living in higher poverty areas experience more acute systemic problems than people in lower poverty areas (e.g., limited access to medical services, healthy and affordable food, quality education, and civic engagement opportunities). Government agencies and researchers have previously identified counties with high rates of poverty over an extended period as targets for increased level of support. While definitions vary, typically, counties are considered to be in persistent poverty if they maintained poverty rates of 20 percent or more for the past 30 years.

To identify counties in persistent poverty, this report incorporates poverty estimates from the 1990 and 2000 Censuses, the 2005–2009 American Community Survey (ACS) 5-year estimates, and the 2015–2019 ACS 5-year estimates. Other governmental agencies have alternative definitions of persistent poverty for programmatic purposes. This has created a need for more consistent methods that can be universally applied and examples of such are described in this report.

This report expands upon the persistent poverty literature by examining subcounty geographies and comparing those results to county results. By using this smaller geography, additional populations that may benefit from targeted intervention are identifiable.