Grant Number:	5R01CA085295-02 Interpret this number
Primary Investigator:	Daniels, Michael
Organization:	Iowa State University
Project Title:	Covariance Estimation for Longitudinal Cancer Data
Fiscal Year:	2002

DESCRIPTION (Applicant's abstract): In statistical modeling the covariance structure is often considered a nuisance, or at least of secondary importance to the mean. However, when the goals of an analysis include estimation of subject-specific effects or prediction, estimation of the covariance structure is very important. This project will develop methodology for improving estimation of covariance structure in longitudinal cancer studies. This will result in increased efficiency in estimation of fixed and random effects, such as subject-specific trajectories, and predictions. Specifically, this project will develop estimators of covariance matrices that are robust to a variety of eigenstructures and/or structural assumptions, develop methods to compute these estimators in hierarchical models, and develop classes of models to account for heterogeneity, both explained and unexplained by covariates, in covariance structures across subjects in longitudinal trials. In sum, this will provide greater flexibility in modeling, and efficiency in making inferences from, longitudinal cancer data. The methods include development of sensible prior distribution from which estimators can be derived that have good properties in small samples and/or in high dimensions and construction of hierarchical models to account for heterogeneous covariance structures across subjects through covariates and/or prior distributions. The common theme will be prior distributions which sh6nk the cova6ance matrix or function toward some parametric form or to some 'average' matrix or function, with the amount of shrinkage determined by the data. Computationally efficient ways to compute the estimators and fit the models will be explored, some of which will involve only minor modifications to standard software.




ARMA Cholesky Factor Models for the Covariance Matrix of Linear Models.
Authors: Lee K. , Baek C. , Daniels M.J. .
Source: Computational Statistics & Data Analysis, 2017 Nov; 115, p. 267-280.
EPub date: 2017-05-18 00:00:00.0.
PMID: 29109594
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A note on posterior predictive checks to assess model fit for incomplete data.
Authors: Xu D. , Chatterjee A. , Daniels M. .
Source: Statistics In Medicine, 2016-11-30 00:00:00.0; 35(27), p. 5029-5039.
EPub date: 2016-11-30 00:00:00.0.
PMID: 27426216
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Inference In Randomized Trials With Death And Missingness
Authors: Wang C. , Scharfstein D.O. , Colantuoni E. , Girard T.D. , Yan Y. .
Source: Biometrics, 2016-10-17 00:00:00.0; , .
PMID: 27753071
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A Framework For Bayesian Nonparametric Inference For Causal Effects Of Mediation
Authors: Kim C. , Daniels M.J. , Marcus B.H. , Roy J.A. .
Source: Biometrics, 2016-08-01 00:00:00.0; , .
PMID: 27479682
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Covariance Partition Priors: A Bayesian Approach to Simultaneous Covariance Estimation for Longitudinal Data.
Authors: Gaskins J.T. , Daniels M.J. .
Source: Journal Of Computational And Graphical Statistics : A Joint Publication Of American Statistical Association, Institute Of Mathematical Statistics, Interface Foundation Of North America, 2016-01-02 00:00:00.0; 25(1), p. 167-186.
EPub date: 2016-01-02 00:00:00.0.
PMID: 27175055
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Quantile regression in the presence of monotone missingness with sensitivity analysis.
Authors: Liu M. , Daniels M.J. , Perri M.G. .
Source: Biostatistics (oxford, England), 2016 Jan; 17(1), p. 108-21.
PMID: 26041008
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Causal inference with longitudinal outcomes and non-ignorable drop-out: Estimating the effect of living alone on cognitive decline.
Authors: Josefsson M. , de Luna X. , Daniels M.J. , Nyberg L. .
Source: Journal Of The Royal Statistical Society. Series C, Applied Statistics, 2016-01-01 00:00:00.0; 65(1), p. 131-144.
EPub date: 2016-01-01 00:00:00.0.
PMID: 26839439
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Bayesian methods for nonignorable dropout in joint models in smoking cessation studies.
Authors: Gaskins J.T. , Daniels M.J. , Marcus B.H. .
Source: Journal Of The American Statistical Association, 2016; 111(516), p. 1454-1465.
EPub date: 2017-01-05 00:00:00.0.
PMID: 29104333
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Pattern mixture models for the analysis of repeated attempt designs.
Authors: Daniels M.J. , Jackson D. , Feng W. , White I.R. .
Source: Biometrics, 2015 Dec; 71(4), p. 1160-7.
PMID: 26149119
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Bayesian modeling of the covariance structure for irregular longitudinal data using the partial autocorrelation function.
Authors: Su L. , Daniels M.J. .
Source: Statistics In Medicine, 2015-05-30 00:00:00.0; 34(12), p. 2004-18.
EPub date: 2015-05-30 00:00:00.0.
PMID: 25762065
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A Flexible Bayesian Approach to Monotone Missing Data in Longitudinal Studies with Nonignorable Missingness with Application to an Acute Schizophrenia Clinical Trial.
Authors: Linero A.R. , Daniels M.J. .
Source: Journal Of The American Statistical Association, 2015 Mar; 110(509), p. 45-55.
PMID: 26236060
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Computationally Efficient Banding Of Large Covariance Matrices For Ordered Data And Connections To Banding The Inverse Cholesky Factor
Authors: Wang Y. , Daniels M.J. .
Source: Journal Of Multivariate Analysis, 2014-09-01 00:00:00.0; 130, p. 21-26.
PMID: 25147413
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A Semiparametric Approach To Simultaneous Covariance Estimation For Bivariate Sparse Longitudinal Data
Authors: Das K. , Daniels M.J. .
Source: Biometrics, 2014 Mar; 70(1), p. 33-43.
PMID: 24400941
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Fully Bayesian Inference Under Ignorable Missingness In The Presence Of Auxiliary Covariates
Authors: Daniels M.J. , Wang C. , Marcus B.H. .
Source: Biometrics, 2014 Mar; 70(1), p. 62-72.
PMID: 24571539
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Sparsity Inducing Prior Distributions For Correlation Matrices Of Longitudinal Data
Authors: Gaskins J.T. , Daniels M.J. , Marcus B.H. .
Source: Journal Of Computational And Graphical Statistics : A Joint Publication Of American Statistical Association, Institute Of Mathematical Statistics, Interface Foundation Of North America, 2014; 23(4), p. 966-984.
PMID: 25382958
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Causal Inference For Bivariate Longitudinal Quality Of Life Data In Presence Of Death By Using Global Odds Ratios
Authors: Lee K. , Daniels M.J. .
Source: Statistics In Medicine, 2013-10-30 00:00:00.0; 32(24), p. 4275-84.
PMID: 23720372
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Flexible Marginalized Models For Bivariate Longitudinal Ordinal Data
Authors: Lee K. , Daniels M.J. , Joo Y. .
Source: Biostatistics (oxford, England), 2013 Jul; 14(3), p. 462-76.
PMID: 23365416
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Bayesian Modeling Of The Dependence In Longitudinal Data Via Partial Autocorrelations And Marginal Variances
Authors: Wang Y. , Daniels M.J. .
Source: Journal Of Multivariate Analysis, 2013-04-01 00:00:00.0; 116, p. 130-140.
PMID: 23645941
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An Exploration Of Fixed And Random Effects Selection For Longitudinal Binary Outcomes In The Presence Of Nonignorable Dropout
Authors: Li N. , Daniels M.J. , Li G. , Elashoff R.M. .
Source: Biometrical Journal. Biometrische Zeitschrift, 2013 Jan; 55(1), p. 17-37.
PMID: 23124889
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A Nonparametric Prior For Simultaneous Covariance Estimation
Authors: Gaskins J.T. , Daniels M.J. .
Source: Biometrika, 2013; 100(1), .
PMID: 24324281
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Bayesian Model Selection For Incomplete Data Using The Posterior Predictive Distribution
Authors: Daniels M.J. , Chatterjee A.S. , Wang C. .
Source: Biometrics, 2012 Dec; 68(4), p. 1055-63.
PMID: 22551040
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Bayesian Inference For The Causal Effect Of Mediation
Authors: Daniels M.J. , Roy J.A. , Kim C. , Hogan J.W. , Perri M.G. .
Source: Biometrics, 2012 Dec; 68(4), p. 1028-36.
PMID: 23005030
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A Bayesian Semiparametric Approach For Incorporating Longitudinal Information On Exposure History For Inference In Case-control Studies
Authors: Bhadra,D. , Daniels,M.J. , Kim,S. , Ghosh,M. , Mukherjee,B. .
Source: Biometrics, 2012 Jun; 68(2), p. 361-70.
PMID: 22313248
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A Note On Mar, Identifying Restrictions, Model Comparison, And Sensitivity Analysis In Pattern Mixture Models With And Without Covariates For Incomplete Data
Authors: Wang,C. , Daniels,M.J. .
Source: Biometrics, 2011 Sep; 67(3), p. 810-8.
PMID: 21361893
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Estimating The Causal Effect Of Low Tidal Volume Ventilation On Survival In Patients With Acute Lung Injury
Authors: Wang W. , Scharfstein D. , Wang C. , Daniels M. , Needham D. , Brower R. , the NHLBI ARDS Clinical Network .
Source: Journal Of The Royal Statistical Society. Series C, Applied Statistics, 2011-08-01 00:00:00.0; 60(4), p. 475-496.
PMID: 22025809
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Multiple Imputation Of Missing Phenotype Data For Qtl Mapping
Authors: Bobb J.F. , Scharfstein D.O. , Daniels M.J. , Collins F.S. , Kelada S. .
Source: Statistical Applications In Genetics And Molecular Biology, 2011; 10(1), p. Article 29.
PMID: 24683667
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Modeling Competing Infectious Pathogens From A Bayesian Perspective: Application To Influenza Studies With Incomplete Laboratory Results
Authors: Yang Y. , Halloran M.E. , Daniels M.J. , Longini I.M. , Burke D.S. , Cummings D.A. .
Source: Journal Of The American Statistical Association, 2010 Dec; 105(492), p. 1310-1322.
PMID: 21472041
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A Bayesian Shrinkage Model For Incomplete Longitudinal Binary Data With Application To The Breast Cancer Prevention Trial
Authors: Wang C. , Daniels M.J. , Scharfstein D.O. , Land S. .
Source: Journal Of The American Statistical Association, 2010 Dec; 105(492), p. 1333-1346.
PMID: 21516191
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Causal Effects Of Treatments For Informative Missing Data Due To Progression/death
Authors: Lee K. , Daniels M.J. , Sargent D.J. .
Source: Journal Of The American Statistical Association, 2010-09-01 00:00:00.0; 105(491), p. 912-929.
PMID: 21318119
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Modeling Covariance Matrices Via Partial Autocorrelations
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Source: Journal Of Multivariate Analysis, 2009-11-01 00:00:00.0; 100(10), p. 2352-2363.
PMID: 20161018
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Joint Models For The Association Of Longitudinal Binary And Continuous Processes With Application To A Smoking Cessation Trial
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Source: Journal Of The American Statistical Association, 2009-06-01 00:00:00.0; 104(486), p. 429-438.
PMID: 20161053
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Discussion Of "missing Data Methods In Longitudinal Studies: A Review" By Ibrahim And Molenberghs
Authors: Daniels M.J. , Wang C. .
Source: Test (madrid, Spain), 2009 May; 18(1), p. 51-58.
PMID: 21949475
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Marginalized Models For Longitudinal Ordinal Data With Application To Quality Of Life Studies
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Source: Statistics In Medicine, 2008-09-20 00:00:00.0; 27(21), p. 4359-80.
PMID: 18613246
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A Flexible Approach To Bayesian Multiple Curve Fitting
Authors: Botts C.H. , Daniels M.J. .
Source: Computational Statistics & Data Analysis, 2008-08-15 00:00:00.0; 52(12), p. 5100-5120.
PMID: 21127724
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A General Class Of Pattern Mixture Models For Nonignorable Dropout With Many Possible Dropout Times
Authors: Roy,J. , Daniels,M.J. .
Source: Biometrics, 2008 Jun; 64(2), p. 538-45.
PMID: 17900312
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A Class Of Markov Models For Longitudinal Ordinal Data
Authors: Lee K. , Daniels M.J. .
Source: Biometrics, 2007 Dec; 63(4), p. 1060-7.
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On Estimation Of Vaccine Efficacy Using Validation Samples With Selection Bias
Authors: Scharfstein D.O. , Halloran M.E. , Chu H. , Daniels M.J. .
Source: Biostatistics (oxford, England), 2006 Oct; 7(4), p. 615-29.
PMID: 16556610
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Longitudinal Profiling Of Health Care Units Based On Continuous And Discrete Patient Outcomes
Authors: Daniels M.J. , Normand S.L. .
Source: Biostatistics (oxford, England), 2006 Jan; 7(1), p. 1-15.
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Underestimation Of Standard Errors In Multi-site Time Series Studies
Authors: Daniels,M.J. , Dominici,F. , Zeger,S. .
Source: Epidemiology (cambridge, Mass.), 2004 Jan; 15(1), p. 57-62.
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Incorporating Prior Beliefs About Selection Bias Into The Analysis Of Randomized Trials With Missing Outcomes
Authors: Scharfstein D.O. , Daniels M.J. , Robins J.M. .
Source: Biostatistics (oxford, England), 2003 Oct; 4(4), p. 495-512.
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Modelling The Random Effects Covariance Matrix In Longitudinal Data
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Source: Statistics In Medicine, 2003-05-30 00:00:00.0; 22(10), p. 1631-47.
PMID: 12720301
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Dynamic Conditionally Linear Mixed Models For Longitudinal Data
Authors: Pourahmadi M. , Daniels M.J. .
Source: Biometrics, 2002 Mar; 58(1), p. 225-31.
PMID: 11890319
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Shrinkage Estimators For Covariance Matrices
Authors: Daniels M.J. , Kass R.E. .
Source: Biometrics, 2001 Dec; 57(4), p. 1173-84.
PMID: 11764258
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