The use of census data for determining race and education as SES indicators: a validation study.
OBJECTIVE
Little research has examined the validity of using census data to determine an individual's socio-economic status (SES), as measured by race and educational level. This study assessed the accuracy of using aggregate level data from United States Census Block Groups in determining race and education SES indicators in a cohort of women from North Carolina.


METHODS
The study analyzed patient data from the Carolina Mammography Registry and 1990 United States Census in 21 North Carolina counties. Women (n = 39,546) were geocoded to their census block group and their block group characteristics (surrogate measures) were validated with their self-reported values on race and education. An analysis was performed to explore whether using these surrogate measures would affect measured associations with the self-reported values.


RESULTS
Whites were accurately identified (84.8%) more consistently than Blacks (14.1%) regardless of their urban/rural status. Women without a high school diploma or equivalent were accurately identified (56.2%) more often than those with higher education levels (45.9%). Analyses using the surrogate measures were significantly different than the true values according to chi-square statistics.


CONCLUSIONS
Use of census data to derive SES indicators tends to be more accurate for the majority than the minority population. Researchers must be sensitive to the ecologic fallacy when using aggregate level data such as the census to determine individual level characteristics.
Kwok
R K
RK
Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7515, USA.
Yankaskas
B C
BC
D001741:Black or African American / Q000706:statistics & numerical data*; D001940:Breast / Q000166:cytology; D002452:Cell Count; D019352:Censuses; D002908:Chronic Disease / Q000453:epidemiology*; D004522:Educational Status; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008327:Mammography / Q000706:statistics & numerical data; D009657:North Carolina / Q000453:epidemiology; D044469:Racial Groups; D012042:Registries; D015203:Reproducibility of Results; D012424:Rural Population; D012959:Socioeconomic Factors; D014505:Urban Population; D044465:White People / Q000706:statistics & numerical data*