Browsing Waterloo Research by Author "Cook, Richard"
Now showing items 21-40 of 43
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Mitigating bias from intermittent measurement of time-dependent covariates in failure time analysis
Jiang, Shu; Cook, Richard J.; Zeng, Leilei (Wiley, 2020-06-15)Cox regression models are routinely fitted to examine the association between time-dependent markers and a failure time when analyzing data from clinical registries. Typically, the marker values are measured periodically ... -
A mixture model for bivariate interval-censored failure times with dependent susceptibility
Jiang, Shu; Cook, Richard J. (Springer, 2020-03-07)Interval-censored failure times arise when the status with respect to an event of interest is only determined at intermittent examination times. In settings where there exists a sub-population of individuals who are not ... -
Multiple imputation for the analysis of incomplete compound variables
Cook, Richard J.; Wu, Changbao; Zhao, Jiwei (Wiley, 2015-06)In many settings interest lies in modelling a compound variable defined as a function of two or more component variables. When one or more of the components are missing, the compound variable is not observed and a strategy ... -
Multistate analysis from cross-sectional and auxiliary samples
Zeng, Leilei; Cook, Richard J.; Lee, Jooyoung (Wiley, 2020-02-20)Epidemiological studies routinely involve cross‐sectional sampling of a population comprised of individuals progressing through life history processes. We consider features of a cross‐sectional sample in terms of the ... -
A Multistate Model for Bivariate Interval-Censored Failure Time Data
Cook, Richard J.; Zeng, Leilei; Lee, Ker-Ai (Wiley, 2008-12)Interval-censored life-history data arise when the events of interest are only detectable at periodic assessments. When interest lies in the occurrence of two such events, bivariate-interval censored event time data are ... -
A new perspective on loss to follow-up in failure time and life history studies
Lawless, Jerald F.; Cook, Richard J. (Wiley, 2019-07-24)A framework is proposed for the joint modeling of life history and loss to follow-up (LTF) processes in cohort studies. This framework provides a basis for discussing independence conditions for LTF and censoring and ... -
On estimands arising from misspecified semiparametric rate-based analysis of recurrent episodic conditions
Lee, Jooyoung; Cook, Richard J. (Wiley, 2019-11-10)Marginal rate-based analyses are widely used for the analysis of recurrent events in clinical trials. In many areas of application, the events are not instantaneous but rather signal the onset of a symptomatic episode ... -
Penalized Regression for Interval-Censored Times of Disease Progression: Selection of HLA Markers in Psoriatic Arthritis
Wu, Ying; Cook, Richard J. (Wiley, 2015-09)Times of disease progression are interval-censored when progression status is only known at a series of assessment times. This situation arises routinely in clinical trials and cohort studies when events of interest are ... -
The polytomous discrimination index for prediction involving multistate processes under intermittent observation
Jiang, Shu; Cook, Richard (John Wiley & Sons Ltd., 2022-08-30)With the increasing importance of predictive modeling in health research comes the need for methods to rigorously assess predictive accuracy. We consider the problem of evaluating the accuracy of predictive models for ... -
Regression with incomplete covariates and left-truncated time-to-event data
Shen, Hua; Cook, Richard J. (Wiley, 2013)Studies of chronic diseases routinely sample individuals subject to conditions on an event time of interest. In epidemiology, for example, prevalent cohort studies aiming to evaluate risk factors for survival following ... -
Regression with incomplete multivariate surrogate responses for a latent covariate
Shen, Hua; Cook, Richard J. (Taylor & Francis, 2020-07-29)We consider the setting in which a categorical exposure variable of interest can only be measured subject to misclassification via surrogate variables. These surrogate variables may represent the classification of an ... -
Response-dependent two-phase sampling designs for biomarker studies
Cook, Richard J.; McIsaac, Michael A. (Wiley, 2014)Two-phase sampling designs are developed and investigated for use in the context of a rheumatology study where interest lies in the association between a biomarker with an expensive assay and disease progression. We ... -
Robust Estimation of Mean Functions and Treatment Effects for Recurrent Events Under Event-Dependent Censoring and Termination: Application to Skeletal Complications in Cancer Metastatic to Bone
Cook, Richard J.; Lakhal-Chaieb, Lajmi; Lee, Ker-Ai; Lawless, Jerald F. (Taylor & Francis, 2009)In clinical trials featuring recurrent clinical events, the definition and estimation of treatment effects involves a number of interesting issues, especially when loss to follow-up may be eventrelated and when terminal ... -
Sample size and robust marginal methods for cluster-randomized trials with censored event times
Cook, Richard J.; Zhong, Yujie (Wiley, 2015-03-15)In cluster-randomized trials, intervention effects are often formulated by specifying marginal models, fitting them under a working independence assumption, and using robust variance estimates to address the association ... -
Score tests based on a finite mixture model of Markov processes under intermittent observation
Jiang, Shu; Cook, Richard J. (Wiley, 2019-07-20)A mixture model is described, which accommodates different Markov processes governing disease progression in a finite set of latent classes. We give special attention to the setting in which individuals are examined ... -
Selection models for efficient two-phase design of family studies
Zhong, Yujie; Cook, Richard (John Wiley & Sons, Ltd., 2021-01-30)Family studies routinely employ biased sampling schemes in which individuals are randomly chosen from a disease registry and genetic and phenotypic data are obtained from their consenting relatives. We view this as a ... -
Semiparametric recurrent event vs time-to-first-event analyses in randomized trials: Estimands and model misspecification
Zhong, Yujie; Cook, Richard (John Wiley & Sons Ltd., 2021-04-20)Insights regarding the merits of recurrent event and time-to-first-event analyses are needed to provide guidance on strategies for analyzing intervention effects in randomized trials involving recurrent event responses. ... -
Sieve estimation in a Markov illness-death process under dual censoring
Cook, Richard J.; Boruvka, Audrey (Oxford Journals, 2016-02-29)Semiparametric methods are well-established for the analysis of a progressive Markov illness-death process observed up to a noninformative right censoring time. However often the intermediate and terminal events are ... -
Statistical Issues in Modeling Chronic Disease in Cohort Studies
Cook, Richard J.; Lawless, Jerald F. (Springer, 2014)Observational cohort studies of individuals with chronic disease provide information on rates of disease progression, the effect of fixed and time-varying risk factors, and the extent of heterogeneity in the course of ... -
Statistical methods for incomplete data: Some results on model misspecification
McIsaac, Michael A.; Cook, Richard J. (Sage Publishing, 2017-02-01)Inverse probability weighted estimating equations and multiple imputation are two of the most studied frameworks for dealing with incomplete data in clinical and epidemiological research. We examine the limiting behaviour ...