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Flexible Additive Risk Models Using Piecewise Constant Hazard Functions

We study a weighted least squares (WLS) estimator for Aalen's additive risk model which allows for a very flexible handling of covariates. We divide the follow-up period into intervals and assume a constant hazard rate in each interval. The model is motivated as a piecewise approximation of a hazard function composed of three parts: arbitrary nonparametric functions for some covariate effects, smoothly varying functions for others, and known (or constant) functions for yet others. The proposed estimator is an extension of the grouped data version of the Huffer-McKeague estimator (1991). Our estimator may also be regarded as a piecewise constant analog of the semiparametric estimates of McKeague & Sasieni (1994), and Lin & Ying (1994). By using a fairly large number of intervals, we should get an essentially semiparametric model similar to the McKeague-Sasieni and Lin-Ying approaches. For our model, since the number of parameters is finite (although large), conventional approaches (such as maximum likelihood) are easy to formulate and implement. The approach is illustrated by simulations, and is applied to data from the Framingham heart study. / A Dissertation Submitted to the Department of Statistics in Partial FulfiLlment of
the Requirements for the Degree of Doctor of Philosophy. / Fall Semester, 2007. / August 10, 2007. / Risk, Additive, Hazard / Includes bibliographical references. / Fred W. Huffer, Professor Directing Dissertation; Alec Kercheval, Outside Committee Member; Dan McGee, Committee Member; Xufeng Niu, Committee Member.
ContributorsUhm, Daiho (authoraut), Huffer, Fred W. (professor directing dissertation), Kercheval, Alec (outside committee member), McGee, Dan (committee member), Niu, Xufeng (committee member), Department of Statistics (degree granting department), Florida State University (degree granting institution)
PublisherFlorida State University, Florida State University
Source SetsFlorida State University
LanguageEnglish, English
Detected LanguageEnglish
TypeText, text
Format1 online resource, computer, application/pdf
RightsThis Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them.

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