Statistics, Department of

 

The R Journal

Date of this Version

7-2018

Document Type

Article

Citation

The R Journal (July 2018) 10(1); Editor: John Verzani

Comments

Copyright 2018, The R Foundation. Open access material. License: CC BY 4.0 International

Abstract

The cchs package contains a function, also called cchs, for analyzing data from a stratified case-cohort study, as used in epidemiology. For data from this type of study, cchs calculates Estimator III of Borgan et al. (2000), which is a score-unbiased estimator for the regression coefficients in the Cox proportional hazards model. From the user’s point of view, the function is similar to coxph (in the survival package) and other widely used model-fitting functions. Convenient software has not previously been available for Estimator III since it is complicated to calculate. SAS and S-Plus code-fragments for the calculation have been published, but cchs is easier to use and more efficient in terms of time and memory, and can cope with much larger datasets. It also avoids several minor approximations and simplifications.

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