Affiliations: [a] National Center for Health Services Research and
Health Care Technology Assessment
Correspondence:
[*]
Address correspondence to Dr. Steven B. Cohen, Senior Biostatistician
National Center for Health Services Research, 5600 Fischers Lane, Room
18A-55, Rockville, Maryland 20857.
Abstract: The National Medical Care Utilization and Expenditure Survey (NMCUES), which has
a complex survey design, was further complicated by combining two independently
drawn national samples of households from the Research Triangle Institute (RTI)
and the National Opinion Research Center (NORC). It is assumed that because the
structures of both national area samples are similar, they are thereby
compatible and allow for the derivation of unbiased national estimates of
relevant health parameters. However, even though the two survey organizations
operate under a common set of survey conditions with comparable samples, the
actual data generated may differ across them, over and above differences due to
pure sampling error. The NORC sample had a higher representation of individuals
living in non-SMSA urban areas, of individuals with fair or poor health status,
and of individuals incapable of performing usual activity. In addition,
significantly higher mean estimates of the number of restricted activity days,
of total charges for dental Visits, for non-doctor visits and for hospital
stays, and of overall total charges, characterized the NORC sample. The
consistent directional difference in these health care estimates indicated a
data collection organization effect was operational in the NMCUES. A comparison
of item non response rates, however, indicated the level of data quality on this
dimension was generally equivalent across survey organizations. Further, the
observed survey design differentials across organizations did not significantly
differ in their impact on the precision in survey estimates. When a data
collection organization effect is operational for a set of related survey
statistics, as in the National Medical Care Utilization and Expenditure Survey,
the use of more than one survey organization should be seriously considered.
