Adapting the Index of Relative Rurality (IRR) to Estimate Rurality at the ZIP Code Level: A Rural Classification System in Health Services Research

• Published in: The Journal of rural health Vol. 32; no. 2; pp. 219 - 227
• Main Authors: Inagami, Sanae, Gao, Shasha, Karimi, Hassan, Shendge, Martine M., Probst, Janice C., Stone, Roslyn A.
• Format: Journal Article
• Language: English
• Published: England Journal of Rural Health 01-03-2016; Blackwell Publishing Ltd; Wiley Subscription Services, Inc
• Subjects: Agricultural economics; Agricultural research; Agriculture departments; Agronomy; Censuses; Classification; Classification systems; Commuting; Data analysis; Economic research; Federal agencies; geography; Government agencies; Health care; Health care policy; Health problems; Health services; health services research; Health Services Research - methods; Humans; index of relative rurality; Medical research; observational data; Physicians; Populations; Postal codes; Primary care; Reproducibility of Results; Residents; Rural areas; rural classification; Rural communities; Rural Health Services - classification; Rural populations; Rurality; Services; Small-Area Analysis; Social services delivery; United States; Veterans; United States; United States > US; Pittsburgh Pennsylvania; USA; index of relative rurality; health services research; rural classification; observational data; geography
• ISSN: 0890-765X; 1748-0361
• DOI: 10.1111/jrh.12148

BACKGROUND: Accurate analysis of health problems facing rural residents depends on how rurality is defined. Health services research relies frequently on the rural urban commuting area (RUCA) codes to estimate rurality at the small area level. We modified the county‐level Index of Relative Rurality (IRR) to the ZIP code level (IRRZIP) to create an alternative small‐area‐level rural classification system. We then compared how the 2 rural classification systems differ in how rural areas and populations are defined and in methodological analysis. METHODS: We linked data for veterans (n = 37,466) who attended the VA Pittsburgh Healthcare System to 2000 United States Census and the US Department of Agriculture's Economic Research Service data. RESULTS: The RUCA and the IRRZIP do not consistently classify the same ZIP code areas and populations as rural. Using the IRRZIP, each 10th increment in increased rurality was associated with a 2.6 increased odds of receiving primary care at a satellite clinic. CONCLUSIONS: The IRRZIP is a straightforward measure that is easy to use and interpret and may be a relevant alternative rural classification system that can be used in health services research.