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dc.contributor.advisorBrown, Elizabeth Ren_US
dc.contributor.authorColey, Rebecca Yatesen_US
dc.date.accessioned2014-10-13T20:01:22Z
dc.date.available2015-12-14T17:55:53Z
dc.date.submitted2014en_US
dc.identifier.otherColey_washington_0250E_13551.pdfen_US
dc.identifier.urihttp://hdl.handle.net/1773/26396
dc.descriptionThesis (Ph.D.)--University of Washington, 2014en_US
dc.description.abstractThe effect of an intervention or exposure on time-to-event is most commonly estimated with the Cox model, which assumes proportional hazards. When heterogeneity in risk is present, the assumption of proportionality is violated and the Cox model's population-averaged estimate of the hazard ratio can underestimate the effect for an individual. In this dissertation, we develop Bayesian hierarchical frailty models that adjust for heterogeneity in risk in a way that reflects the sources of heterogeneity. We focus on the compound Poisson distribution, as it reflects a biological risk mechanism seen in many applications where an individual's risk of an event is the result of independent, competing exposure processes and it allows that some individuals have no risk of an event. In Chapter 2, we outline a hierarchical definition of the compound Poisson distribution and demonstrate Bayesian estimation of a hierarchical compound Poisson frailty model. In Chapter 3, we extend the model proposed in Chapter 2 to allow frailty distributions to vary across latent risk classes, resulting in a compound Poisson mixture frailty distribution. Risk-related covariates are used to classify participants into latent risk groups. We conclude with a discussion of future work, including ideas for a gamma frailty model with subject-specific parameters for situations in which exposure processes are observed.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.rightsCopyright is held by the individual authors.en_US
dc.subjectBayesian analysis; Frailty; Heterogeneity; Hierarchical model; HIV prevention; Survival analysisen_US
dc.subject.otherBiostatisticsen_US
dc.titleBayesian Hierarchical Frailty Models for Heterogeneity in Risken_US
dc.typeThesisen_US
dc.embargo.termsRestrict to UW for 1 year -- then make Open Accessen_US


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