At. Geronimus et J. Bound, USE OF CENSUS-BASED AGGREGATE VARIABLES TO PROXY FOR SOCIOECONOMIC GROUP - EVIDENCE FROM NATIONAL SAMPLES, American journal of epidemiology, 148(5), 1998, pp. 475-486
Increasingly, investigators append census-based socioeconomic characte
ristics of residential areas to individual records to address the prob
lem of inadequate socioeconomic information on health data sets. Littl
e empirical attention has been given to the validity of this approach.
The authors estimate health outcome equations using samples from nati
onally representative data sets linked to census data, They investigat
e whether statistical power is sensitive to the timing of census data
collection or to the level of aggregation of the census data; whether
different census items are conceptually distinct; and whether the use
of multiple aggregate measures in health outcome equations improves pr
ediction compared with a single aggregate measure. The authors find li
ttle difference in estimates when using 1970 compared with 1980 US Bur
eau of the Census data or zip code compared with tract level variables
. However, aggregate variables are highly multicollinear, Associations
of health outcomes with aggregate measures are substantially weaker t
han with microlevel measures. The authors conclude that aggregate meas
ures can not be interpreted as if they were microlevel variables nor s
hould a specific aggregate measure be interpreted to represent the eff
ects of what it is labeled.