Estimation Of Odds Ratio Function With Censored Data Jae-Kee, Song Kyungpook National University, Department of Statistics #1370, Sankyuk-dong, Puk-gu Taegu City, 702-701, Korea (Rep.) jksong@kyungpook.ac.kr Jung-Suk, Kim Taegu Polytechnic College, Department of Computer Science #395, Manchon-dong, Susung-gu Taegu City, 706-711, Korea (Rep.) Z941095@rose0.kyungpook.ac.kr Dong-Myung, Jeong National Statistical Office, Statistical Information & Data Management Bureau Government Complex Taejon, #920, Dunsan-dong, So-gu Taejon City, 302-701, Korea (Rep.) dmjeong@nso.go.kr 1. Introduction and Summary Odds ratio is often used for comparing the odds that a subject will survive among subjects who have been exposed to a risk factor to the odds that a subject will survive in subjects who have not been exposed. Since odds ratio provides a kind of snapshot analysis at a particular time point, a single odds ratio alone does not show the whole picture. Therefore it is natural for odds ratio to be extended in order to see trend over the entire time span. In this paper we define odds ratio function, provide three estimators, and compare them when there is censoring. The first one is a nonparametric estimator based on the Nelson-Aalen estimator of the cumulative hazard function, and the others are obtained using the concept of the usual odds ratio estimate. Asymptotics are also investigated and confidence intervals for odds ratio function are constructed. The performances of the proposed estimators finally are compared and the results are illustrated using real data. REFERENCES Andersen, P. K., Borgan, ∅., Gill, R. D. and Keiding, N. (1993). Statistical Models Based on Counting Processes, Springer-Verlag, New York. Breslow, N. E. (1996). Statistics in Epidemiology : The Case-Control Study, Journal of the American Statistical Association 91, 14-28. Pearce, Neil. (1993). What does the odds ratio estimate in a case-control study? International Journal of Epidemiology 22, 1189-1192. RÉSUMÉ Le ratio de différence seul ne montre pas tous ce qui concerne la mesure de la risque relative des deux groupes. Dans ce papier, donc, on définit la fonction du ratio de différence qui peut en étiduer le cours sur toute l'étendu du temps. Trois estimateurs sont étudiés et comparés, et le résultat est illustré avec le data réel.