Show simple item record

Flexible Methods for Clustered Event History Data.

dc.contributor.authorLiu, Dandanen_US
dc.date.accessioned2011-06-10T18:17:15Z
dc.date.availableNO_RESTRICTIONen_US
dc.date.available2011-06-10T18:17:15Z
dc.date.issued2011en_US
dc.date.submitteden_US
dc.identifier.urihttps://hdl.handle.net/2027.42/84488
dc.description.abstractThis dissertation investigates three interesting problems in clustered event history data. The first project considers a positive stable frailty proportional hazards model for clustered failure time data, with the frailty distribution allowed to depend on cluster-level covariates. We connect the cluster-level covariates with the dependence parameter through a link function. The mathematical property of the positive stable distribution enables proportionality for both the marginal and conditional hazard functions. As a result, the marginal regression parameter equals the product of the dependence parameter and the conditional regression parameter. We utilize this special feature and propose a two-step estimation approach, where the marginal regression parameters are obtained in the first step and the regression parameters for the link function are obtained in the second step based on the conditional intensity model. The second project proposes a computationally efficient marginal proportional rates model with piecewise-constant baseline rate function for clustered recurrent event data. The parametric specification of the baseline rate function enables the modeling of intermittent counts instead of recurrent event times, which results in data reduction and remedies computational issues resulting from the size of the databases. Large-sample distributions are derived for the proposed estimators. We show that the proposed method can be implemented using standard statistical software for Cox regression. An application based on national hospitalization data for end stage renal disease patients is provided. The third project investigates a fixed center effects model for recurrent event data with center effects multiplicatively acting on the rate functions. When the number of centers is large, traditional estimation methods that treat centers as categorical variables have many parameters and are sometimes not feasible to implement, especially with large number of distinct recurrent event times. We propose a new estimation method for center effects which avoids including indicator variables for centers. We then show that the center effect can be consistently estimated by the ratio of the observed cumulative number of events to the corresponding expected quantity in a center. Large sample results are developed for the proposed estimators. The method is then applied to national hospitalization data for end stage renal disease patients.en_US
dc.language.isoen_USen_US
dc.subjectPositive Stable Frailty Modelen_US
dc.subjectRecurrent Event With Terminating Eventen_US
dc.subjectProportional Rates Modelen_US
dc.subjectPiecewise-constant Baseline Ratesen_US
dc.subjectFixed Center Effects Modelen_US
dc.subjectHospitalization Studyen_US
dc.titleFlexible Methods for Clustered Event History Data.en_US
dc.typeThesisen_US
dc.description.thesisdegreenamePhDen_US
dc.description.thesisdegreedisciplineBiostatisticsen_US
dc.description.thesisdegreegrantorUniversity of Michigan, Horace H. Rackham School of Graduate Studiesen_US
dc.contributor.committeememberKalbfleisch, John D.en_US
dc.contributor.committeememberSchaubel, Douglas E.en_US
dc.contributor.committeememberWheeler, Jacken_US
dc.contributor.committeememberZhang, Minen_US
dc.subject.hlbsecondlevelPublic Healthen_US
dc.subject.hlbtoplevelHealth Sciencesen_US
dc.subject.hlbtoplevelScienceen_US
dc.description.bitstreamurlhttp://deepblue.lib.umich.edu/bitstream/2027.42/84488/1/dandanl_1.pdf
dc.owningcollnameDissertations and Theses (Ph.D. and Master's)


Files in this item

Show simple item record

Remediation of Harmful Language

The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.

Accessibility

If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.