Comparing Adaptive Interventions Using Data Arising from a SMART: With Application to Autism, ADHD, and Mood Disorders

Size: px
Start display at page:

Download "Comparing Adaptive Interventions Using Data Arising from a SMART: With Application to Autism, ADHD, and Mood Disorders"

Transcription

1 Comparing Adaptive Interventions Using Data Arising from a SMART: With Application to Autism, ADHD, and Mood Disorders Daniel Almirall, Xi Lu, Connie Kasari, Inbal N-Shani, Univ. of Michigan, Univ. of California Los Angeles University of Chicago May 1, 2015 Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

2 Outline Background: Adaptive Interventions and SMARTs (Autism) Marginal Model and Efficiency Considerations in Estimation (Autism) Modeling Longitudinal Outcomes in a SMART (Autism and ADHD) Adaptive Implementation Interventions (Mood Disorders) Other SMART Designs in Mental Health (Autism, Adolescent Depression) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

3 Background: Adaptive Interventions and SMART Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

4 Sequential, Individualized Treatment is Often Needed Management of many health disorders often entails a sequential, individualized approach treatment is adapted and re-adapted over time This type of sequential decision-making is necessary when there is high level of individual heterogeneity in response to treatment. great treatment effect heterogeneity, no widely effective treatment, there are widely effective treatments but they are burdensome, costly, or carry side effects. Adaptive Interventions (AI) provide one way to operationalize the strategies (e.g., continue, augment, switch, step-down) leading to individualized sequences of treatment. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

5 Definition of an Adaptive Intervention A sequence of decision rules that specify whether, how, when (timing), and based on which measures, to alter the dosage (duration, frequency or amount), type, or delivery of treatment(s) at decision stages in the course of care. aka: dynamic treatment regime/regimen, adaptive treatment strategy, treatment policy, treatment algorithms, medication algorithms, etc. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

6 Example of an Adaptive Intervention in Autism (PI: Kasari) For older, minimally verbal children with autism spectrum disorder Stage One JASP for 12 weeks; Stage Two At the end of week 12, determine early sign of response: IF slow responder: Augment JASP with AAC for 12 weeks; ELSE IF responder: Maintain JASP for 12 weeks. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

7 Example of an Adaptive Intervention in Autism (PI: Kasari) For older, minimally verbal children with autism spectrum disorder Stage One JASP for 12 weeks; Stage Two At the end of week 12, determine early sign of response: IF slow responder: Augment JASP with AAC for 12 weeks; ELSE IF responder: Maintain JASP for 12 weeks. JASP First stage Treatment (Weeks 1 12) Responders Slow Responders End of Week 12 Responder Status Continue: JASP Augment: JASP + AAC Second stage Treatment (Weeks 13 24) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

8 But AAC s are costly (time and money). So there are important unanswered questions when building an Adaptive Intervention with AAC. For example... Is it better to provide AAC from the start? How long to wait before declaring a child a slow responder to JASP? Can we identify which children would benefit from AAC from the start vs those who would benefit from delayed AAC? For slow responders, what is the effect of providing the AAC vs intensifying JASP (not providing AAC)? Sequential Multiple Assignment Randomized Trials (SMARTs) can be used to address such questions empirically, using experimental design principles. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

9 What is a Sequential Multiple Assignment Randomized Trial (SMART)? A type of multi-stage randomized trial design. At each stage, subjects randomized to a set of feasible/ethical treatment options. Treatment options latter stages may be restricted by early response status SMARTs were developed explicitly for the purpose of building a high-quality Adaptive Intervention. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

10 Example of a SMART in Autism Research (N = 61) PI: Kasari (UCLA). (ages 5-8; planned N = 98 but recruitment difficult, despite multi-site. Wk12 response rates much higher than anticipated.) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

11 Scientific Aim is to compare the 3 embedded AIs. (a 1, a 2 ) = (1, 1) (JASP,JASP+) Subgroups A+C (a 1, a 2 ) = (1, 1) (JASP,AAC) Subgroups A+B (a 1, a 2 ) = ( 1,.) (AAC,AAC+) Subgroups D+E Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

12 A Marginal Model for Y (Social Communicative Utterances) and Efficiency Considerations in Estimation Other work includes work by Robins (1995, 2008, etc.), Orellana et al. (2010), Hirano et al. (2003), Chafee and van der Laan (2012), Bembom and van der Laan (2007, 2008), Williamson et al. (2013), Wang et al. (2012) and others... Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

13 The marginal model for comparing AIs. E[Y (a 1, a 2 ) X ] = β 0 + η T X + β 1 a 1 + β 2 I (a 1 = 1)a 2 e.g., 2β 1 + β 2 = (AAC,AAC+) vs (JASP,JASP+) But how do we estimate this with observed data {X i, A 1i, R i, A 2i, Y i }? Regressing Y on [1, X, A 1, I (A 1 = 1)A 2 ] does not work. Why? By design, there is an under-representation of slow responders to JASP who get JASP+ (or JASP+AAC). How do we account for the fact that responders to JASP are consistent with two of the embedded AIs? Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

14 Recycling-and-Weighting Regression (RWR) Estimator Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

15 Recycling-and-Weighting Regression Estimator (RWR) Statistical foundation found in work by Orellana, Rotnitzky and Robins: Robins JM, Orellana L, Rotnitzky A. Estimation and extrapolation in optimal treatment and testing strategies. Statistics in Medicine Jul; 27: Orellana L, Rotnitzky A, Robins JM. Dynamic Regime Marginal Structural Mean Models for Estimation of Optimal Dynamic Treatment Regimes, Parts I and II. Int J Biostat. 2010; 6(2): Article 8 and 9. Very nicely explained and implemented with SMART data in: Nahum-Shani I, Qian M, Almirall D, et al. Experimental design and primary data analysis methods for comparing adaptive interventions. Psychol Methods Dec; 17(4): Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

16 Improving the Efficiency of the RWR by Estimating the Known Weights with Covariates By design, we know the true weights. Since Pr(A 1 ) = 1/2 and Pr(A 2 = 1 A 1 = 1, R = 0) = 1/2, then W = 4I {A 1 = 1, R = 0} + 2I { everyone else }. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

17 Improving the Efficiency of the RWR by Estimating the Known Weights with Covariates By design, we know the true weights. Since Pr(A 1 ) = 1/2 and Pr(A 2 = 1 A 1 = 1, R = 0) = 1/2, then W = 4I {A 1 = 1, R = 0} + 2I { everyone else }. Robins and colleagues (1995), Hirano et al (2003) and many others describe potential gains in statistical efficiency by estimating the known weights using auxiliary baseline (L 1 ) and time-varying (L 2 ) covariate information. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

18 Improving the Efficiency of the RWR by Estimating the Known Weights with Covariates By design, we know the true weights. Since Pr(A 1 ) = 1/2 and Pr(A 2 = 1 A 1 = 1, R = 0) = 1/2, then W = 4I {A 1 = 1, R = 0} + 2I { everyone else }. Robins and colleagues (1995), Hirano et al (2003) and many others describe potential gains in statistical efficiency by estimating the known weights using auxiliary baseline (L 1 ) and time-varying (L 2 ) covariate information. Example using the Autism SMART data: The observed data is now {L 1i, X i, A 1i, R i, L 2i, A 2i, Y i } Use logistic regression to get p 1 = Pr(A 1 L 1, X ) Use logistic regression to get p 2 = Pr(A 2 L 1, X, A 1 = 1, R = 0, L 2 ). Use Ŵ = I {A 1 = 1, R = 0}/( p 1 p 2 ) + I { everyone else }/ p 1. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

19 Improving the Efficiency of the RWR by Estimating the Known Weights with Covariates By design, we know the true weights. Since Pr(A 1 ) = 1/2 and Pr(A 2 = 1 A 1 = 1, R = 0) = 1/2, then W = 4I {A 1 = 1, R = 0} + 2I { everyone else }. Robins and colleagues (1995), Hirano et al (2003) and many others describe potential gains in statistical efficiency by estimating the known weights using auxiliary baseline (L 1 ) and time-varying (L 2 ) covariate information. Example using the Autism SMART data: The observed data is now {L 1i, X i, A 1i, R i, L 2i, A 2i, Y i } Use logistic regression to get p 1 = Pr(A 1 L 1, X ) Use logistic regression to get p 2 = Pr(A 2 L 1, X, A 1 = 1, R = 0, L 2 ). Use Ŵ = I {A 1 = 1, R = 0}/( p 1 p 2 ) + I { everyone else }/ p 1. The key is to choose L t s that are highly correlated with Y! Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

20 Sim: Relative RMSE for (AAC,AAC+) vs (JASP,JASP+) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

21 Results from an Analysis of the Autism SMART Y = is Socially Communicative Utterances at Week 24 (SD=34.6). W (known) Ŵ (est.) ESTIMAND EST SE PVAL EST SE PVAL (AAC,AAC+) < < 0.01 (JASP,AAC) < < 0.01 (JASP,JASP+) < < 0.01 (AAC,AAC+) vs (JASP,JASP+) < < 0.01 (AAC,AAC+) vs (JASP,AAC) (JASP,AAC) vs (JASP,JASP+) Apparent greater efficiency was observed in the analysis of the autism SMART (about 4% - 21% apparent improvement). Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

22 Analysis of Longitudinal Outcomes in a SMART Other work in this space includes work by Li (2014) and Miyahara and Wahed (2012). Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

23 Methodological Challenges 1 Modeling: The intermixing of repeated measures and sequential randomizations requires new modeling considerations to account for the fact that embedded AIs will share paths/trajectories at different time points (...more difficult the more complex the SMART is...) 2 Statistical: Develop an estimator that takes advantage of the within person correlation in the outcome over time (...think GEE...) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

24 An Example Marginal Model for Longitudinal Outcomes Y t : # Socially Communicative Utterances at week t. t = 0, 12, 24, 36 Ideally, the longitudinal model should 1 permit deflections/changes in trajectories at week 12, 2 respect temporal ordering, and 3 respect shared trajectory paths An example is the following piece-wise linear model: E[Y t (a 1, a 2 ) X ] = β 0 + η T X + 1 t 12 {β 1 t + β 2 ta 1 } + 1 t>12 {12β β 2 a 1 + β 3 (t 12) + β 4 (t 12)a 1 + β 5 (t 12)a 1 a 2 } where X s are mean-centered baseline covariates. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

25 Analysis of Longitudinal Outcomes in the Autism SMART Average level of spoken communication over 36 weeks (i.e., AUC/36) for each AI AI Estimate 95% CI (AAC,AAC+) 51.4 [45.6, 57.3] (JASP,AAC) 40.7 [34.5, 46.8] (JASP,JASP+) 39.3 [32.6, 46.0] Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

26 Child Attention Deficit Hyperactivity Disorder (ADHD) PI: Pelham (FIU) (N = 153; ages 6-12; 8 month study; monthly non-response based on two teacher ratings (ITB < 0.75 and IRS > 1 domain) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

27 Analysis of Longitudinal Outcomes in the ADHD SMART Y t = Classroom performance over the school year under each AI Classroom performance DTR AI (MED, MED+) BMOD.INT BMOD.MED (MED, MED.BMOD MED+BMD) (BMD,BMD+MED) MED.INT (BMD,BMD+) Color Purple Blue Green Red Time (months) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

28 Methodological Challenges 1 Modeling: The intermixing of repeated measures and sequential randomizations requires new modeling considerations to account for the fact that embedded AIs will share paths/trajectories at different time points (...more difficult the more complex the SMART is...) 2 Statistical: Develop an estimator that takes advantage of the within person correlation in the outcome over time (...think GEE...) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

29 Statistical: RWR Estimator for Longitudinal Outcomes Obtain estimates of (η, β) by solving the following estimating equation: 0 = 1 N N I i (a 1, a 2 )D i (X i, a 1, a 2 )V 1 i W i (Y i µ i (X i, a 1, a 2 ; β, η)), i=1 (a 1,a 2 ) where I i (a 1, a 2 ): indicates if i s txt sequence is consistent with (a 1, a 2 ) Y i : a vector of longitudinal outcomes, i.e. (Y i,0, Y i,12, Y i,24, Y i,36 ) T ; µ i a vector of corresponding conditional means; ( µi (X i,āi ;β,η) ) T D i : the design matrix, i.e., µ i (X i,āi ;β,η) β T η ; T W i : a diagonal matrix containing IPW (known or estimated); V i : working covariance matrix for Y i. Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

30 Statistical: RWR Estimator for Longitudinal Outcomes We implemented it using the following estimating equation: 0 = 1 M M D i (X i, Ā i )V 1 i W i (Y i µ i (X i, Ā i ; β, η)), i=1 where M = N+ # JASP Slow Responders Y i : a vector of longitudinal outcomes, i.e. (Y i,0, Y i,12, Y i,24, Y i,36 ) T ; µ i a vector of corresponding conditional means; ( µi (X i,ā i ;β,η) ) T D i : the design matrix, i.e., µ i (X i,ā i ;β,η) β T η ; T W i : a diagonal matrix containing IPW (known or estimated); V i : working covariance matrix for Y i. This facilitates using existing software (SEs requires more work). Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

31 Statistical: The choice of V and the form of W For the case of V = I (independence working covariance structure), W may have the form W i = w w where w i = 4I {A 1 = 1, R = 0} + 2I { everyone else }. However, for V I (e.g., autoregressive or exchangeable structure), W must have the form w W i = 0 w w w But why? Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

32 Why W = diag(1/(pr(a 1 )Pr(A 2 A 1, R))) when V I? Some intuition: 0 = 1 M M D i (X i, Ā i )V 1 i W i (Y i µ i (X i, Ā i ; β, η)) i=1 =... + D i,t=24 (X i, A i1, A i2 ) v 12,24 w 12 (Y i,12 µ i,12 (X i, A i1 ; β, η)) +... This cross-product term Is not mean zero if w 12 = 2 = 1/Pr(A 1 ), leading to bias Is mean zero if w 12 = 1/(Pr(A 1 )Pr(A 2 A 1, R)) Pepe and Anderson (1994, cautioning about GEE s with time-varying covariates, in general; Stijn Vansteelandt (2007, cautioning about MSMs) Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

33 An Exciting and SMART Development in Mental Health Implementation Science Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

34 Adaptive Implementation Intervention in Mental Health PI: Kilbourne; Co-I: Almirall (CO/AR/MI; Aim is to improve uptake of psychosocial intervention for mood disorders; primary aim compared initial REP+EF vs REP+EF+IF.)

35 Other SMART Designs in Mental Health Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

36 Adaptive Treatment Strategies for Adolescent Depression PI: Gunlicks-Stoessel (Univ of Minnesota); Co-I: Almirall (Univ Michigan)

37 Interventions for Minimally Verbal Children with Autism PI: Kasari(UCLA), Kaiser(Vanderbilt), Smith(Rochester), Lord(Cornell), Almirall(Mich)

38 Interventions for Minimally Verbal Children with Autism PI: Kasari(UCLA), Kaiser(Vanderbilt), Smith(Rochester), Lord(Cornell), Almirall(Mich) R JASP (joint attention and social play) Non-Responders (Parent training no feasible) Responders (Blended txt unnecessary) R R JASP + DTT Continue JASP Continue JASP JASP + Parent Training DTT (discrete trials training) Non-Responders (Parent training not feasible) R JASP + DTT Continue DTT Responders (Blended txt unnecessary) R Continue DTT DTT + Parent Training

39 Thank you! Questions? More About SMART: More papers and these slides on my website (Daniel Almirall): dalmiral/ me with questions about this presentation: Daniel Almirall: Thanks to NIDA and NIMH for Funding this Research: P50DA10075, R03MH , RC4MH Almirall, Lu, Kasari, N-Shani Design and Analysis of SMART May 1, / 35

arxiv: v1 [stat.me] 14 Jul 2016

arxiv: v1 [stat.me] 14 Jul 2016 Comparing cluster-level dynamic treatment regimens using sequential, multiple assignment, randomized trials: Regression estimation and sample size considerations arxiv:1607.04039v1 [stat.me] 14 Jul 016

More information

Estimating Optimal Dynamic Treatment Regimes from Clustered Data

Estimating Optimal Dynamic Treatment Regimes from Clustered Data Estimating Optimal Dynamic Treatment Regimes from Clustered Data Bibhas Chakraborty Department of Biostatistics, Columbia University bc2425@columbia.edu Society for Clinical Trials Annual Meetings Boston,

More information

Q learning. A data analysis method for constructing adaptive interventions

Q learning. A data analysis method for constructing adaptive interventions Q learning A data analysis method for constructing adaptive interventions SMART First stage intervention options coded as 1(M) and 1(B) Second stage intervention options coded as 1(M) and 1(B) O1 A1 O2

More information

Lecture 9: Learning Optimal Dynamic Treatment Regimes. Donglin Zeng, Department of Biostatistics, University of North Carolina

Lecture 9: Learning Optimal Dynamic Treatment Regimes. Donglin Zeng, Department of Biostatistics, University of North Carolina Lecture 9: Learning Optimal Dynamic Treatment Regimes Introduction Refresh: Dynamic Treatment Regimes (DTRs) DTRs: sequential decision rules, tailored at each stage by patients time-varying features and

More information

SEQUENTIAL MULTIPLE ASSIGNMENT RANDOMIZATION TRIALS WITH ENRICHMENT (SMARTER) DESIGN

SEQUENTIAL MULTIPLE ASSIGNMENT RANDOMIZATION TRIALS WITH ENRICHMENT (SMARTER) DESIGN SEQUENTIAL MULTIPLE ASSIGNMENT RANDOMIZATION TRIALS WITH ENRICHMENT (SMARTER) DESIGN Ying Liu Division of Biostatistics, Medical College of Wisconsin Yuanjia Wang Department of Biostatistics & Psychiatry,

More information

arxiv: v1 [stat.ap] 17 Mar 2018

arxiv: v1 [stat.ap] 17 Mar 2018 Power Analysis in a SMART Design: Sample Size Estimation for Determining the Best Dynamic Treatment Regime arxiv:1804.04587v1 [stat.ap] 17 Mar 2018 William J. Artman Department of Biostatistics and Computational

More information

Set-valued dynamic treatment regimes for competing outcomes

Set-valued dynamic treatment regimes for competing outcomes Set-valued dynamic treatment regimes for competing outcomes Eric B. Laber Department of Statistics, North Carolina State University JSM, Montreal, QC, August 5, 2013 Acknowledgments Zhiqiang Tan Jamie

More information

Structural Nested Mean Models for Assessing Time-Varying Effect Moderation. Daniel Almirall

Structural Nested Mean Models for Assessing Time-Varying Effect Moderation. Daniel Almirall 1 Structural Nested Mean Models for Assessing Time-Varying Effect Moderation Daniel Almirall Center for Health Services Research, Durham VAMC & Dept. of Biostatistics, Duke University Medical Joint work

More information

Estimation of Optimal Treatment Regimes Via Machine Learning. Marie Davidian

Estimation of Optimal Treatment Regimes Via Machine Learning. Marie Davidian Estimation of Optimal Treatment Regimes Via Machine Learning Marie Davidian Department of Statistics North Carolina State University Triangle Machine Learning Day April 3, 2018 1/28 Optimal DTRs Via ML

More information

A Sampling of IMPACT Research:

A Sampling of IMPACT Research: A Sampling of IMPACT Research: Methods for Analysis with Dropout and Identifying Optimal Treatment Regimes Marie Davidian Department of Statistics North Carolina State University http://www.stat.ncsu.edu/

More information

Comparative effectiveness of dynamic treatment regimes

Comparative effectiveness of dynamic treatment regimes Comparative effectiveness of dynamic treatment regimes An application of the parametric g- formula Miguel Hernán Departments of Epidemiology and Biostatistics Harvard School of Public Health www.hsph.harvard.edu/causal

More information

Adaptive Trial Designs

Adaptive Trial Designs Adaptive Trial Designs Wenjing Zheng, Ph.D. Methods Core Seminar Center for AIDS Prevention Studies University of California, San Francisco Nov. 17 th, 2015 Trial Design! Ethical:!eg.! Safety!! Efficacy!

More information

Integrated approaches for analysis of cluster randomised trials

Integrated approaches for analysis of cluster randomised trials Integrated approaches for analysis of cluster randomised trials Invited Session 4.1 - Recent developments in CRTs Joint work with L. Turner, F. Li, J. Gallis and D. Murray Mélanie PRAGUE - SCT 2017 - Liverpool

More information

IP WEIGHTING AND MARGINAL STRUCTURAL MODELS (CHAPTER 12) BIOS IPW and MSM

IP WEIGHTING AND MARGINAL STRUCTURAL MODELS (CHAPTER 12) BIOS IPW and MSM IP WEIGHTING AND MARGINAL STRUCTURAL MODELS (CHAPTER 12) BIOS 776 1 12 IPW and MSM IP weighting and marginal structural models ( 12) Outline 12.1 The causal question 12.2 Estimating IP weights via modeling

More information

Structural Nested Mean Models for Assessing Time-Varying Effect Moderation. Daniel Almirall

Structural Nested Mean Models for Assessing Time-Varying Effect Moderation. Daniel Almirall 1 Structural Nested Mean Models for Assessing Time-Varying Effect Moderation Daniel Almirall Center for Health Services Research, Durham VAMC & Duke University Medical, Dept. of Biostatistics Joint work

More information

Extending causal inferences from a randomized trial to a target population

Extending causal inferences from a randomized trial to a target population Extending causal inferences from a randomized trial to a target population Issa Dahabreh Center for Evidence Synthesis in Health, Brown University issa dahabreh@brown.edu January 16, 2019 Issa Dahabreh

More information

Geoffrey T. Wodtke. University of Toronto. Daniel Almirall. University of Michigan. Population Studies Center Research Report July 2015

Geoffrey T. Wodtke. University of Toronto. Daniel Almirall. University of Michigan. Population Studies Center Research Report July 2015 Estimating Heterogeneous Causal Effects with Time-Varying Treatments and Time-Varying Effect Moderators: Structural Nested Mean Models and Regression-with-Residuals Geoffrey T. Wodtke University of Toronto

More information

Personalized Treatment Selection Based on Randomized Clinical Trials. Tianxi Cai Department of Biostatistics Harvard School of Public Health

Personalized Treatment Selection Based on Randomized Clinical Trials. Tianxi Cai Department of Biostatistics Harvard School of Public Health Personalized Treatment Selection Based on Randomized Clinical Trials Tianxi Cai Department of Biostatistics Harvard School of Public Health Outline Motivation A systematic approach to separating subpopulations

More information

Methods for inferring short- and long-term effects of exposures on outcomes, using longitudinal data on both measures

Methods for inferring short- and long-term effects of exposures on outcomes, using longitudinal data on both measures Methods for inferring short- and long-term effects of exposures on outcomes, using longitudinal data on both measures Ruth Keogh, Stijn Vansteelandt, Rhian Daniel Department of Medical Statistics London

More information

A Gate-keeping Approach for Selecting Adaptive Interventions under General SMART Designs

A Gate-keeping Approach for Selecting Adaptive Interventions under General SMART Designs 1 / 32 A Gate-keeping Approach for Selecting Adaptive Interventions under General SMART Designs Tony Zhong, DrPH Icahn School of Medicine at Mount Sinai (Feb 20, 2019) Workshop on Design of mhealth Intervention

More information

Evaluation of Viable Dynamic Treatment Regimes in a Sequentially Randomized Trial of Advanced Prostate Cancer

Evaluation of Viable Dynamic Treatment Regimes in a Sequentially Randomized Trial of Advanced Prostate Cancer Evaluation of Viable Dynamic Treatment Regimes in a Sequentially Randomized Trial of Advanced Prostate Cancer Lu Wang, Andrea Rotnitzky, Xihong Lin, Randall E. Millikan, and Peter F. Thall Abstract We

More information

Modeling Longitudinal Count Data with Excess Zeros and Time-Dependent Covariates: Application to Drug Use

Modeling Longitudinal Count Data with Excess Zeros and Time-Dependent Covariates: Application to Drug Use Modeling Longitudinal Count Data with Excess Zeros and : Application to Drug Use University of Northern Colorado November 17, 2014 Presentation Outline I and Data Issues II Correlated Count Regression

More information

Randomization-Based Inference With Complex Data Need Not Be Complex!

Randomization-Based Inference With Complex Data Need Not Be Complex! Randomization-Based Inference With Complex Data Need Not Be Complex! JITAIs JITAIs Susan Murphy 07.18.17 HeartSteps JITAI JITAIs Sequential Decision Making Use data to inform science and construct decision

More information

Estimating the effects of timevarying treatments in the presence of time-varying confounding

Estimating the effects of timevarying treatments in the presence of time-varying confounding Estimating the effects of timevarying treatments in the presence of time-varying confounding An application to neighborhood effects on high school graduation David J. Harding, University of Michigan (joint

More information

Micro-Randomized Trials & mhealth. S.A. Murphy NRC 8/2014

Micro-Randomized Trials & mhealth. S.A. Murphy NRC 8/2014 Micro-Randomized Trials & mhealth S.A. Murphy NRC 8/2014 mhealth Goal: Design a Continually Learning Mobile Health Intervention: HeartSteps + Designing a Micro-Randomized Trial 2 Data from wearable devices

More information

Categorical and Zero Inflated Growth Models

Categorical and Zero Inflated Growth Models Categorical and Zero Inflated Growth Models Alan C. Acock* Summer, 2009 *Alan C. Acock, Department of Human Development and Family Sciences, Oregon State University, Corvallis OR 97331 (alan.acock@oregonstate.edu).

More information

Estimating Causal Effects of Organ Transplantation Treatment Regimes

Estimating Causal Effects of Organ Transplantation Treatment Regimes Estimating Causal Effects of Organ Transplantation Treatment Regimes David M. Vock, Jeffrey A. Verdoliva Boatman Division of Biostatistics University of Minnesota July 31, 2018 1 / 27 Hot off the Press

More information

Running Head: Effect Heterogeneity with Time-varying Treatments and Moderators ESTIMATING HETEROGENEOUS CAUSAL EFFECTS WITH TIME-VARYING

Running Head: Effect Heterogeneity with Time-varying Treatments and Moderators ESTIMATING HETEROGENEOUS CAUSAL EFFECTS WITH TIME-VARYING Running Head: Effect Heterogeneity with Time-varying Treatments and Moderators ESTIMATING HETEROGENEOUS CAUSAL EFFECTS WITH TIME-VARYING TREATMENTS AND TIME-VARYING EFFECT MODERATORS: STRUCTURAL NESTED

More information

Econometric Causality

Econometric Causality Econometric (2008) International Statistical Review, 76(1):1-27 James J. Heckman Spencer/INET Conference University of Chicago Econometric The econometric approach to causality develops explicit models

More information

Daniel Almirall 1, Daniel F. McCaffrey 2, Beth Ann Griffin 2, Rajeev Ramchand 2, Susan A. Murphy 1

Daniel Almirall 1, Daniel F. McCaffrey 2, Beth Ann Griffin 2, Rajeev Ramchand 2, Susan A. Murphy 1 1 Examining moderated effects of additional adolescent substance use treatment: Structural nested mean model estimation using inverse-weighted regression-with-residuals Daniel Almirall 1, Daniel F. McCaffrey

More information

Daniel Almirall 1, Daniel F. McCaffrey 2, Beth Ann Griffin 2, Rajeev Ramchand 2, Susan A. Murphy 1

Daniel Almirall 1, Daniel F. McCaffrey 2, Beth Ann Griffin 2, Rajeev Ramchand 2, Susan A. Murphy 1 1 Examining moderated effects of additional adolescent substance use treatment: Structural nested mean model estimation using inverse-weighted regression-with-residuals Daniel Almirall 1, Daniel F. McCaffrey

More information

Longitudinal Data Analysis Using Stata Paul D. Allison, Ph.D. Upcoming Seminar: May 18-19, 2017, Chicago, Illinois

Longitudinal Data Analysis Using Stata Paul D. Allison, Ph.D. Upcoming Seminar: May 18-19, 2017, Chicago, Illinois Longitudinal Data Analysis Using Stata Paul D. Allison, Ph.D. Upcoming Seminar: May 18-19, 217, Chicago, Illinois Outline 1. Opportunities and challenges of panel data. a. Data requirements b. Control

More information

Assessing Time-Varying Causal Effect Moderation in Mobile Health

Assessing Time-Varying Causal Effect Moderation in Mobile Health Assessing Time-Varying Causal Effect Moderation in Mobile Health arxiv:1601.00237v3 [stat.me] 17 Aug 2016 Audrey Boruvka 1, Daniel Almirall 2, Katie Witkiewitz 3, and Susan A. Murphy 1,2 1 Department of

More information

Three-Level Modeling for Factorial Experiments With Experimentally Induced Clustering

Three-Level Modeling for Factorial Experiments With Experimentally Induced Clustering Three-Level Modeling for Factorial Experiments With Experimentally Induced Clustering John J. Dziak The Pennsylvania State University Inbal Nahum-Shani The University of Michigan Copyright 016, Penn State.

More information

Lecture 2: Constant Treatment Strategies. Donglin Zeng, Department of Biostatistics, University of North Carolina

Lecture 2: Constant Treatment Strategies. Donglin Zeng, Department of Biostatistics, University of North Carolina Lecture 2: Constant Treatment Strategies Introduction Motivation We will focus on evaluating constant treatment strategies in this lecture. We will discuss using randomized or observational study for these

More information

BIOS 6649: Handout Exercise Solution

BIOS 6649: Handout Exercise Solution BIOS 6649: Handout Exercise Solution NOTE: I encourage you to work together, but the work you submit must be your own. Any plagiarism will result in loss of all marks. This assignment is based on weight-loss

More information

Longitudinal Data Analysis Using SAS Paul D. Allison, Ph.D. Upcoming Seminar: October 13-14, 2017, Boston, Massachusetts

Longitudinal Data Analysis Using SAS Paul D. Allison, Ph.D. Upcoming Seminar: October 13-14, 2017, Boston, Massachusetts Longitudinal Data Analysis Using SAS Paul D. Allison, Ph.D. Upcoming Seminar: October 13-14, 217, Boston, Massachusetts Outline 1. Opportunities and challenges of panel data. a. Data requirements b. Control

More information

Achieving Optimal Covariate Balance Under General Treatment Regimes

Achieving Optimal Covariate Balance Under General Treatment Regimes Achieving Under General Treatment Regimes Marc Ratkovic Princeton University May 24, 2012 Motivation For many questions of interest in the social sciences, experiments are not possible Possible bias in

More information

Combining Equity and Efficiency. in Health Care. John Hooker. Joint work with H. P. Williams, LSE. Imperial College, November 2010

Combining Equity and Efficiency. in Health Care. John Hooker. Joint work with H. P. Williams, LSE. Imperial College, November 2010 Combining Equity and Efficiency in Health Care John Hooker Carnegie Mellon University Joint work with H. P. Williams, LSE Imperial College, November 2010 1 Just Distribution The problem: How to distribute

More information

Causality II: How does causal inference fit into public health and what it is the role of statistics?

Causality II: How does causal inference fit into public health and what it is the role of statistics? Causality II: How does causal inference fit into public health and what it is the role of statistics? Statistics for Psychosocial Research II November 13, 2006 1 Outline Potential Outcomes / Counterfactual

More information

Causal inference in epidemiological practice

Causal inference in epidemiological practice Causal inference in epidemiological practice Willem van der Wal Biostatistics, Julius Center UMC Utrecht June 5, 2 Overview Introduction to causal inference Marginal causal effects Estimating marginal

More information

Modern Mediation Analysis Methods in the Social Sciences

Modern Mediation Analysis Methods in the Social Sciences Modern Mediation Analysis Methods in the Social Sciences David P. MacKinnon, Arizona State University Causal Mediation Analysis in Social and Medical Research, Oxford, England July 7, 2014 Introduction

More information

TREE-BASED REINFORCEMENT LEARNING FOR ESTIMATING OPTIMAL DYNAMIC TREATMENT REGIMES. University of Michigan, Ann Arbor

TREE-BASED REINFORCEMENT LEARNING FOR ESTIMATING OPTIMAL DYNAMIC TREATMENT REGIMES. University of Michigan, Ann Arbor Submitted to the Annals of Applied Statistics TREE-BASED REINFORCEMENT LEARNING FOR ESTIMATING OPTIMAL DYNAMIC TREATMENT REGIMES BY YEBIN TAO, LU WANG AND DANIEL ALMIRALL University of Michigan, Ann Arbor

More information

Assessing Time-Varying Causal Effect. Moderation

Assessing Time-Varying Causal Effect. Moderation Assessing Time-Varying Causal Effect JITAIs Moderation HeartSteps JITAI JITAIs Susan Murphy 11.07.16 JITAIs Outline Introduction to mobile health Causal Treatment Effects (aka Causal Excursions) (A wonderfully

More information

Switching-state Dynamical Modeling of Daily Behavioral Data

Switching-state Dynamical Modeling of Daily Behavioral Data Switching-state Dynamical Modeling of Daily Behavioral Data Randy Ardywibowo Shuai Huang Cao Xiao Shupeng Gui Yu Cheng Ji Liu Xiaoning Qian Texas A&M University University of Washington IBM T.J. Watson

More information

Step-by-Step Guidelines for Propensity Score Weighting with Two Groups. Beth Ann Griffin Daniel McCaffrey

Step-by-Step Guidelines for Propensity Score Weighting with Two Groups. Beth Ann Griffin Daniel McCaffrey Step-by-Step Guidelines for Propensity Score Weighting with Two Groups Beth Ann Griffin Daniel McCaffrey 1 Four key steps 1) Choose the primary treatment effect of interest (ATE or ATT) 2) Estimate propensity

More information

Predicting Long-term Exposures for Health Effect Studies

Predicting Long-term Exposures for Health Effect Studies Predicting Long-term Exposures for Health Effect Studies Lianne Sheppard Adam A. Szpiro, Johan Lindström, Paul D. Sampson and the MESA Air team University of Washington CMAS Special Session, October 13,

More information

Stat 579: Generalized Linear Models and Extensions

Stat 579: Generalized Linear Models and Extensions Stat 579: Generalized Linear Models and Extensions Linear Mixed Models for Longitudinal Data Yan Lu April, 2018, week 15 1 / 38 Data structure t1 t2 tn i 1st subject y 11 y 12 y 1n1 Experimental 2nd subject

More information

Treatment Effects. Christopher Taber. September 6, Department of Economics University of Wisconsin-Madison

Treatment Effects. Christopher Taber. September 6, Department of Economics University of Wisconsin-Madison Treatment Effects Christopher Taber Department of Economics University of Wisconsin-Madison September 6, 2017 Notation First a word on notation I like to use i subscripts on random variables to be clear

More information

Relating Latent Class Analysis Results to Variables not Included in the Analysis

Relating Latent Class Analysis Results to Variables not Included in the Analysis Relating LCA Results 1 Running Head: Relating LCA Results Relating Latent Class Analysis Results to Variables not Included in the Analysis Shaunna L. Clark & Bengt Muthén University of California, Los

More information

Semiparametric Regression and Machine Learning Methods for Estimating Optimal Dynamic Treatment Regimes

Semiparametric Regression and Machine Learning Methods for Estimating Optimal Dynamic Treatment Regimes Semiparametric Regression and Machine Learning Methods for Estimating Optimal Dynamic Treatment Regimes by Yebin Tao A dissertation submitted in partial fulfillment of the requirements for the degree of

More information

Estimating Post-Treatment Effect Modification With Generalized Structural Mean Models

Estimating Post-Treatment Effect Modification With Generalized Structural Mean Models Estimating Post-Treatment Effect Modification With Generalized Structural Mean Models Alisa Stephens Luke Keele Marshall Joffe December 5, 2013 Abstract In randomized controlled trials, the evaluation

More information

Targeted Maximum Likelihood Estimation for Dynamic Treatment Regimes in Sequential Randomized Controlled Trials

Targeted Maximum Likelihood Estimation for Dynamic Treatment Regimes in Sequential Randomized Controlled Trials From the SelectedWorks of Paul H. Chaffee June 22, 2012 Targeted Maximum Likelihood Estimation for Dynamic Treatment Regimes in Sequential Randomized Controlled Trials Paul Chaffee Mark J. van der Laan

More information

multilevel modeling: concepts, applications and interpretations

multilevel modeling: concepts, applications and interpretations multilevel modeling: concepts, applications and interpretations lynne c. messer 27 october 2010 warning social and reproductive / perinatal epidemiologist concepts why context matters multilevel models

More information

Mixed-Effects Pattern-Mixture Models for Incomplete Longitudinal Data. Don Hedeker University of Illinois at Chicago

Mixed-Effects Pattern-Mixture Models for Incomplete Longitudinal Data. Don Hedeker University of Illinois at Chicago Mixed-Effects Pattern-Mixture Models for Incomplete Longitudinal Data Don Hedeker University of Illinois at Chicago This work was supported by National Institute of Mental Health Contract N44MH32056. 1

More information

Technical Track Session I: Causal Inference

Technical Track Session I: Causal Inference Impact Evaluation Technical Track Session I: Causal Inference Human Development Human Network Development Network Middle East and North Africa Region World Bank Institute Spanish Impact Evaluation Fund

More information

Analysis of propensity score approaches in difference-in-differences designs

Analysis of propensity score approaches in difference-in-differences designs Author: Diego A. Luna Bazaldua Institution: Lynch School of Education, Boston College Contact email: diego.lunabazaldua@bc.edu Conference section: Research methods Analysis of propensity score approaches

More information

Survival models and health sequences

Survival models and health sequences Survival models and health sequences Walter Dempsey University of Michigan July 27, 2015 Survival Data Problem Description Survival data is commonplace in medical studies, consisting of failure time information

More information

Graphical Representation of Causal Effects. November 10, 2016

Graphical Representation of Causal Effects. November 10, 2016 Graphical Representation of Causal Effects November 10, 2016 Lord s Paradox: Observed Data Units: Students; Covariates: Sex, September Weight; Potential Outcomes: June Weight under Treatment and Control;

More information

Application of Item Response Theory Models for Intensive Longitudinal Data

Application of Item Response Theory Models for Intensive Longitudinal Data Application of Item Response Theory Models for Intensive Longitudinal Data Don Hedeker, Robin Mermelstein, & Brian Flay University of Illinois at Chicago hedeker@uic.edu Models for Intensive Longitudinal

More information

Mixture modelling of recurrent event times with long-term survivors: Analysis of Hutterite birth intervals. John W. Mac McDonald & Alessandro Rosina

Mixture modelling of recurrent event times with long-term survivors: Analysis of Hutterite birth intervals. John W. Mac McDonald & Alessandro Rosina Mixture modelling of recurrent event times with long-term survivors: Analysis of Hutterite birth intervals John W. Mac McDonald & Alessandro Rosina Quantitative Methods in the Social Sciences Seminar -

More information

Modeling Mediation: Causes, Markers, and Mechanisms

Modeling Mediation: Causes, Markers, and Mechanisms Modeling Mediation: Causes, Markers, and Mechanisms Stephen W. Raudenbush University of Chicago Address at the Society for Resesarch on Educational Effectiveness,Washington, DC, March 3, 2011. Many thanks

More information

e author and the promoter give permission to consult this master dissertation and to copy it or parts of it for personal use. Each other use falls

e author and the promoter give permission to consult this master dissertation and to copy it or parts of it for personal use. Each other use falls e author and the promoter give permission to consult this master dissertation and to copy it or parts of it for personal use. Each other use falls under the restrictions of the copyright, in particular

More information

Analysing longitudinal data when the visit times are informative

Analysing longitudinal data when the visit times are informative Analysing longitudinal data when the visit times are informative Eleanor Pullenayegum, PhD Scientist, Hospital for Sick Children Associate Professor, University of Toronto eleanor.pullenayegum@sickkids.ca

More information

Growth Curve Modeling Approach to Moderated Mediation for Longitudinal Data

Growth Curve Modeling Approach to Moderated Mediation for Longitudinal Data Growth Curve Modeling Approach to Moderated Mediation for Longitudinal Data JeeWon Cheong Department of Health Education & Behavior University of Florida This research was supported in part by NIH grants

More information

Time-Varying Causal. Treatment Effects

Time-Varying Causal. Treatment Effects Time-Varying Causal JOOLHEALTH Treatment Effects Bar-Fit Susan A Murphy 12.14.17 HeartSteps SARA Sense 2 Stop Disclosures Consulted with Sanofi on mobile health engagement and adherence. 2 Outline Introduction

More information

Using modern statistical methodology for validating and reporti. Outcomes

Using modern statistical methodology for validating and reporti. Outcomes Using modern statistical methodology for validating and reporting Patient Reported Outcomes Dept. of Biostatistics, Univ. of Copenhagen joint DSBS/FMS Meeting October 2, 2014, Copenhagen Agenda 1 Indirect

More information

Covariate Balancing Propensity Score for General Treatment Regimes

Covariate Balancing Propensity Score for General Treatment Regimes Covariate Balancing Propensity Score for General Treatment Regimes Kosuke Imai Princeton University October 14, 2014 Talk at the Department of Psychiatry, Columbia University Joint work with Christian

More information

Recitation Notes 6. Konrad Menzel. October 22, 2006

Recitation Notes 6. Konrad Menzel. October 22, 2006 Recitation Notes 6 Konrad Menzel October, 006 Random Coefficient Models. Motivation In the empirical literature on education and earnings, the main object of interest is the human capital earnings function

More information

Causal Mediation Analysis in R. Quantitative Methodology and Causal Mechanisms

Causal Mediation Analysis in R. Quantitative Methodology and Causal Mechanisms Causal Mediation Analysis in R Kosuke Imai Princeton University June 18, 2009 Joint work with Luke Keele (Ohio State) Dustin Tingley and Teppei Yamamoto (Princeton) Kosuke Imai (Princeton) Causal Mediation

More information

Compare Predicted Counts between Groups of Zero Truncated Poisson Regression Model based on Recycled Predictions Method

Compare Predicted Counts between Groups of Zero Truncated Poisson Regression Model based on Recycled Predictions Method Compare Predicted Counts between Groups of Zero Truncated Poisson Regression Model based on Recycled Predictions Method Yan Wang 1, Michael Ong 2, Honghu Liu 1,2,3 1 Department of Biostatistics, UCLA School

More information

ASSESSING THE EFFECT OF TREATMENT REGIMES ON LONGITUDINAL OUTCOME DATA: APPLICATION TO REVAMP STUDY OF DEPRESSION

ASSESSING THE EFFECT OF TREATMENT REGIMES ON LONGITUDINAL OUTCOME DATA: APPLICATION TO REVAMP STUDY OF DEPRESSION Journal of Statistical Research 2012, Vol. 46, No. 2, pp. 233-254 ISSN 0256-422 X ASSESSING THE EFFECT OF TREATMENT REGIMES ON LONGITUDINAL OUTCOME DATA: APPLICATION TO REVAMP STUDY OF DEPRESSION SACHIKO

More information

Causal mediation analysis: Definition of effects and common identification assumptions

Causal mediation analysis: Definition of effects and common identification assumptions Causal mediation analysis: Definition of effects and common identification assumptions Trang Quynh Nguyen Seminar on Statistical Methods for Mental Health Research Johns Hopkins Bloomberg School of Public

More information

Implementing Precision Medicine: Optimal Treatment Regimes and SMARTs. Anastasios (Butch) Tsiatis and Marie Davidian

Implementing Precision Medicine: Optimal Treatment Regimes and SMARTs. Anastasios (Butch) Tsiatis and Marie Davidian Implementing Precision Medicine: Optimal Treatment Regimes and SMARTs Anastasios (Butch) Tsiatis and Marie Davidian Department of Statistics North Carolina State University http://www4.stat.ncsu.edu/~davidian

More information

Causal Effect Models for Realistic Individualized Treatment and Intention to Treat Rules

Causal Effect Models for Realistic Individualized Treatment and Intention to Treat Rules University of California, Berkeley From the SelectedWorks of Maya Petersen March, 2007 Causal Effect Models for Realistic Individualized Treatment and Intention to Treat Rules Mark J van der Laan, University

More information

Comparing Change Scores with Lagged Dependent Variables in Models of the Effects of Parents Actions to Modify Children's Problem Behavior

Comparing Change Scores with Lagged Dependent Variables in Models of the Effects of Parents Actions to Modify Children's Problem Behavior Comparing Change Scores with Lagged Dependent Variables in Models of the Effects of Parents Actions to Modify Children's Problem Behavior David R. Johnson Department of Sociology and Haskell Sie Department

More information

Principles Underlying Evaluation Estimators

Principles Underlying Evaluation Estimators The Principles Underlying Evaluation Estimators James J. University of Chicago Econ 350, Winter 2019 The Basic Principles Underlying the Identification of the Main Econometric Evaluation Estimators Two

More information

Modification and Improvement of Empirical Likelihood for Missing Response Problem

Modification and Improvement of Empirical Likelihood for Missing Response Problem UW Biostatistics Working Paper Series 12-30-2010 Modification and Improvement of Empirical Likelihood for Missing Response Problem Kwun Chuen Gary Chan University of Washington - Seattle Campus, kcgchan@u.washington.edu

More information

Combining multiple observational data sources to estimate causal eects

Combining multiple observational data sources to estimate causal eects Department of Statistics, North Carolina State University Combining multiple observational data sources to estimate causal eects Shu Yang* syang24@ncsuedu Joint work with Peng Ding UC Berkeley May 23,

More information

DATA-ADAPTIVE VARIABLE SELECTION FOR

DATA-ADAPTIVE VARIABLE SELECTION FOR DATA-ADAPTIVE VARIABLE SELECTION FOR CAUSAL INFERENCE Group Health Research Institute Department of Biostatistics, University of Washington shortreed.s@ghc.org joint work with Ashkan Ertefaie Department

More information

SAS Macro for Generalized Method of Moments Estimation for Longitudinal Data with Time-Dependent Covariates

SAS Macro for Generalized Method of Moments Estimation for Longitudinal Data with Time-Dependent Covariates Paper 10260-2016 SAS Macro for Generalized Method of Moments Estimation for Longitudinal Data with Time-Dependent Covariates Katherine Cai, Jeffrey Wilson, Arizona State University ABSTRACT Longitudinal

More information

Nonrespondent subsample multiple imputation in two-phase random sampling for nonresponse

Nonrespondent subsample multiple imputation in two-phase random sampling for nonresponse Nonrespondent subsample multiple imputation in two-phase random sampling for nonresponse Nanhua Zhang Division of Biostatistics & Epidemiology Cincinnati Children s Hospital Medical Center (Joint work

More information

University of California, Berkeley

University of California, Berkeley University of California, Berkeley U.C. Berkeley Division of Biostatistics Working Paper Series Year 2015 Paper 334 Targeted Estimation and Inference for the Sample Average Treatment Effect Laura B. Balzer

More information

Robustness to Parametric Assumptions in Missing Data Models

Robustness to Parametric Assumptions in Missing Data Models Robustness to Parametric Assumptions in Missing Data Models Bryan Graham NYU Keisuke Hirano University of Arizona April 2011 Motivation Motivation We consider the classic missing data problem. In practice

More information

Harvard University. Harvard University Biostatistics Working Paper Series

Harvard University. Harvard University Biostatistics Working Paper Series Harvard University Harvard University Biostatistics Working Paper Series Year 2015 Paper 197 On Varieties of Doubly Robust Estimators Under Missing Not at Random With an Ancillary Variable Wang Miao Eric

More information

University of California, Berkeley

University of California, Berkeley University of California, Berkeley U.C. Berkeley Division of Biostatistics Working Paper Series Year 2009 Paper 251 Nonparametric population average models: deriving the form of approximate population

More information

The impact of covariance misspecification in multivariate Gaussian mixtures on estimation and inference

The impact of covariance misspecification in multivariate Gaussian mixtures on estimation and inference The impact of covariance misspecification in multivariate Gaussian mixtures on estimation and inference An application to longitudinal modeling Brianna Heggeseth with Nicholas Jewell Department of Statistics

More information

Selection endogenous dummy ordered probit, and selection endogenous dummy dynamic ordered probit models

Selection endogenous dummy ordered probit, and selection endogenous dummy dynamic ordered probit models Selection endogenous dummy ordered probit, and selection endogenous dummy dynamic ordered probit models Massimiliano Bratti & Alfonso Miranda In many fields of applied work researchers need to model an

More information

Estimation of direct causal effects.

Estimation of direct causal effects. University of California, Berkeley From the SelectedWorks of Maya Petersen May, 2006 Estimation of direct causal effects. Maya L Petersen, University of California, Berkeley Sandra E Sinisi Mark J van

More information

Causal Inference with Big Data Sets

Causal Inference with Big Data Sets Causal Inference with Big Data Sets Marcelo Coca Perraillon University of Colorado AMC November 2016 1 / 1 Outlone Outline Big data Causal inference in economics and statistics Regression discontinuity

More information

Discussion of Missing Data Methods in Longitudinal Studies: A Review by Ibrahim and Molenberghs

Discussion of Missing Data Methods in Longitudinal Studies: A Review by Ibrahim and Molenberghs Discussion of Missing Data Methods in Longitudinal Studies: A Review by Ibrahim and Molenberghs Michael J. Daniels and Chenguang Wang Jan. 18, 2009 First, we would like to thank Joe and Geert for a carefully

More information

Growth Mixture Model

Growth Mixture Model Growth Mixture Model Latent Variable Modeling and Measurement Biostatistics Program Harvard Catalyst The Harvard Clinical & Translational Science Center Short course, October 28, 2016 Slides contributed

More information

Group Sequential Designs: Theory, Computation and Optimisation

Group Sequential Designs: Theory, Computation and Optimisation Group Sequential Designs: Theory, Computation and Optimisation Christopher Jennison Department of Mathematical Sciences, University of Bath, UK http://people.bath.ac.uk/mascj 8th International Conference

More information

Whether to use MMRM as primary estimand.

Whether to use MMRM as primary estimand. Whether to use MMRM as primary estimand. James Roger London School of Hygiene & Tropical Medicine, London. PSI/EFSPI European Statistical Meeting on Estimands. Stevenage, UK: 28 September 2015. 1 / 38

More information

Describing Change over Time: Adding Linear Trends

Describing Change over Time: Adding Linear Trends Describing Change over Time: Adding Linear Trends Longitudinal Data Analysis Workshop Section 7 University of Georgia: Institute for Interdisciplinary Research in Education and Human Development Section

More information

Multi-level Models: Idea

Multi-level Models: Idea Review of 140.656 Review Introduction to multi-level models The two-stage normal-normal model Two-stage linear models with random effects Three-stage linear models Two-stage logistic regression with random

More information

Estimating the Mean Response of Treatment Duration Regimes in an Observational Study. Anastasios A. Tsiatis.

Estimating the Mean Response of Treatment Duration Regimes in an Observational Study. Anastasios A. Tsiatis. Estimating the Mean Response of Treatment Duration Regimes in an Observational Study Anastasios A. Tsiatis http://www.stat.ncsu.edu/ tsiatis/ Introduction to Dynamic Treatment Regimes 1 Outline Description

More information

Introduction to causal identification. Nidhiya Menon IGC Summer School, New Delhi, July 2015

Introduction to causal identification. Nidhiya Menon IGC Summer School, New Delhi, July 2015 Introduction to causal identification Nidhiya Menon IGC Summer School, New Delhi, July 2015 Outline 1. Micro-empirical methods 2. Rubin causal model 3. More on Instrumental Variables (IV) Estimating causal

More information

arxiv: v1 [stat.me] 8 Jun 2016

arxiv: v1 [stat.me] 8 Jun 2016 Principal Score Methods: Assumptions and Extensions Avi Feller UC Berkeley Fabrizia Mealli Università di Firenze Luke Miratrix Harvard GSE arxiv:1606.02682v1 [stat.me] 8 Jun 2016 June 9, 2016 Abstract

More information

Accepted Manuscript. Comparing different ways of calculating sample size for two independent means: A worked example

Accepted Manuscript. Comparing different ways of calculating sample size for two independent means: A worked example Accepted Manuscript Comparing different ways of calculating sample size for two independent means: A worked example Lei Clifton, Jacqueline Birks, David A. Clifton PII: S2451-8654(18)30128-5 DOI: https://doi.org/10.1016/j.conctc.2018.100309

More information