title: Calculating multirace categories and race-specific rates: a cautionary note to rural health researchers and analysts.
abstract: BACKGROUND
  Revised federal standards for racial and ethnic data have resulted in 57 new self-selected multirace categories that cannot be directly compared with traditional "one-race-only" categories. "Bridge methods" are available, but each produces different estimates of single-race populations, raising concern about the potential influence on calculated rates for rural and nonmetropolitan areas.
  
  
  OBJECTIVE
  to examine the potential impact of several bridge methods when calculating race-specific mortality rates.
  
  
  METHODS
  Population and mortality data were collected for 75 counties in Arkansas, and race-specific mortality rates were calculated using 3 deterministic bridging methods: (1) Equal Fractions, (2) Largest Group, and (3) Largest Group Other Than White. The mortality rates were compared at the state and metropolitan/nonmetropolitan levels, as well as for 4 rural substate regions.
  
  
  RESULTS
  Variable rates were obtained from different methods. Estimated mortality rates for the largest single-race groups, White and Black, varied only slightly by method at the state and nonmetropolitan/metropolitan levels. The rural substate regions with the smallest Black populations showed the greatest variation between method-estimated rates for Blacks.
  
  
  CONCLUSIONS
  The results suggest that the smallest minority race categories are exceedingly susceptible to the impact of bridge method selection, especially in nonmetropolitan substate regions.
authors.affiliation: University of Arkansas, Fayetteville 72703, USA. thodgson@uark.edu
authors.forename: Todd W
authors.initials: TW
authors.lastname: Hodgson
authors.forename: Frank L
authors.initials: FL
authors.lastname: Farmer
mesh_terms: D001131:Arkansas / Q000453:epidemiology; D015340:Epidemiologic Research Design; D005006:Ethnicity / Q000145:classification* / Q000706:statistics & numerical data; D006306:Health Surveys; D006801:Humans; D009026:Mortality; D044469:Racial Groups / Q000145:classification*; D012423:Rural Health / Q000145:classification / Q000706:statistics & numerical data*