Address correspondence to Marc N. Elliott, Ph.D., RAND Corporation, 1776 Main Street, P.O. Box 2138, Santa Monica, CA 90407-2138; e-mail: email@example.com. Daniel F. McCaffrey, Ph.D., is with the RAND Corporation, Pittsburgh, PA. Brian K. Finch, Ph.D., is with the San Diego State University, San Diego, CA. David J. Klein, M.S., is with the Children's Hospital Boston, Boston, MA. Nate Orr, M.S., and Megan K. Beckett, Ph.D., are with the RAND Corporation, Santa Monica, CA. Nicole Lurie, M.D., M.S., is with the RAND Corporation, Washington, DC.
Improving Disparity Estimates for Rare Racial/Ethnic Groups with Trend Estimation and Kalman Filtering: An Application to the National Health Interview Survey
Article first published online: 27 JUL 2009
© Health Research and Educational Trust
Health Services Research
Volume 44, Issue 5p1, pages 1622–1639, October 2009
How to Cite
Elliott, M. N., McCaffrey, D. F., Finch, B. K., Klein, D. J., Orr, N., Beckett, M. K. and Lurie, N. (2009), Improving Disparity Estimates for Rare Racial/Ethnic Groups with Trend Estimation and Kalman Filtering: An Application to the National Health Interview Survey. Health Services Research, 44: 1622–1639. doi: 10.1111/j.1475-6773.2009.01000.x
- Issue published online: 1 SEP 2009
- Article first published online: 27 JUL 2009
- Health disparities;
- American Indians;
- borrowing strength;
- cross-sectional data
Objective. Single-year estimates of health disparities in small racial/ethnic groups are often insufficiently precise to guide policy, whereas estimates that are pooled over multiple years may not accurately describe current conditions. While collecting additional data is costly, innovative analytic approaches may improve the accuracy and utility of existing data. We developed an application of the Kalman filter in order to make more efficient use of extant data.
Data Source. We used 1997–2004 National Health Interview Survey data on the prevalence of health outcomes for two racial/ethnic subgroups: American Indians/Alaska Natives and Chinese Americans.
Study Design. We modified the Kalman filter to generate more accurate current-year prevalence estimates for small racial/ethnic groups by efficiently aggregating past years of cross-sectional survey data within racial/ethnic groups. We compared these new estimates and their accuracy to simple current-year prevalence estimates.
Principal Findings. For 18 of 19 outcomes, the modified Kalman filter approach reduced the error of current-year estimates for each of the two groups by 20–35 percent—equivalent to increasing current-year sample sizes for these groups by 56–135 percent.
Conclusions. This approach could increase the accuracy of health measures for small groups using extant data, with virtually no additional cost other than those related to analytical processes.