A Weighted-Least-Squares Estimation Approach to Comparing Trends in Age-Adjusted Cancer Rates across Overlapping Regions

10.6339/JDS.2010.08(4).626

Kimberly A. Walters；Yi Li；Ram C. Tiwari；Zhao-Hui Zou

Age-adjusted cancer rates ； annual percent change (APC) ； cancer surveillance ； trends ； weighted-Least-Squares estimation ； hypothesis testing

Journal of Data Science

8卷4期（2010 / 10 / 01）

631 - 644

英文

Li and Tiwari (2008) recently developed a corrected Z-test statistic for comparing the trends in cancer age-adjusted mortality and incidence rates across overlapping geographic regions, by properly adjusting for the correlation between the slopes of the fitted simple linear regression equations. One of their key assumptions is that the error variances have unknown but common variance. However, since the age-adjusted rates are linear combinations of mortality or incidence counts, arising naturally from an underlying Poisson process, this constant variance assumption may be violated. This paper develops a weighted-least-squares based test that incorporates heteroscedastic error variances, and thus significantly extends the work of Li and Tiwari. The proposed test generally outperforms the aforementioned test through simulations and through application to the age-adjusted mortality data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute.