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xiii | |
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xv | |
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xix | |
Preface |
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xxi | |
Acknowledgments |
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xxiii | |
Authors |
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xxv | |
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Section I Setting the Stage |
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3 | (6) |
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1.1 Understanding the Problem |
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3 | (2) |
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5 | (3) |
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8 | (1) |
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2 Why Are Estimands Important? |
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9 | (8) |
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9 | (1) |
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10 | (2) |
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2.3 Considerations for Differing Stakeholders |
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12 | (1) |
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2.4 Considerations for Differing Clinical Situations |
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13 | (1) |
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14 | (3) |
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3 Estimands and How to Define Them |
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17 | (18) |
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17 | (1) |
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3.2 Study Development Process Chart |
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17 | (2) |
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3.3 Process for Defining Estimands |
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19 | (6) |
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19 | (1) |
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3.3.2 Identifying Intercurrent Events |
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19 | (3) |
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3.3.3 Defining the Treatment Regimen of Interest |
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22 | (1) |
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3.3.4 Overview of Strategies for Handling Intercurrent Events |
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23 | (2) |
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3.4 Defining the Estimand |
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25 | (1) |
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3.5 Special Considerations in Defining Estimands |
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26 | (3) |
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3.5.1 Estimands for Safety Outcomes |
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26 | (1) |
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3.5.2 Estimands for Early-Phase Trials |
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26 | (1) |
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3.5.3 Estimands for Scenarios When Treatment and Outcomes Do Not Occur Concurrently |
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27 | (1) |
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3.5.4 Estimands for Quality-of-Life Evaluation in Trials with Many Deaths |
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27 | (1) |
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3.5.5 Estimands for Assessing Non-inferiority |
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28 | (1) |
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3.6 Trial Design and Conduct Considerations |
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29 | (3) |
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29 | (1) |
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3.6.2 Data Collection and Trial Conduct Considerations |
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29 | (2) |
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3.6.3 Trial Design Considerations |
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31 | (1) |
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3.7 A Note on Missing Data |
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32 | (1) |
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3.8 A Note on the Intention to Treat Principle |
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32 | (2) |
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34 | (1) |
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4 Strategies for Dealing with Intercurrent Events |
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35 | (14) |
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35 | (1) |
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4.2 Treatment Policy Strategy |
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35 | (2) |
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37 | (2) |
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4.4 Hypothetical Strategy |
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39 | (2) |
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4.5 Principal Stratification Strategy |
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41 | (2) |
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4.6 While-on-Treatment Strategy |
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43 | (1) |
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4.7 Assumptions Behind the Strategies for Dealing with Intercurrent Events |
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44 | (2) |
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4.7.1 General Assumptions |
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44 | (1) |
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4.7.2 Treatment Policy Strategy Assumptions |
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44 | (1) |
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4.7.3 Composite Strategy Assumptions |
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45 | (1) |
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4.7.4 Hypothetical Strategy Assumptions |
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45 | (1) |
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4.7.5 Principal Stratification Assumptions |
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45 | (1) |
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4.7.6 While-on-Treatment Strategy Assumptions |
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46 | (1) |
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4.8 Risk-Benefit Implications |
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46 | (1) |
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46 | (3) |
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5 Examples from Actual Clinical Trials in Choosing and Specifying Estimands |
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49 | (24) |
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49 | (2) |
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5.2 Example 1: A Proof of Concept Trial in Major Depressive Disorder |
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51 | (4) |
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51 | (1) |
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52 | (1) |
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52 | (3) |
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5.3 Example 2: A Confirmatory Trial in Asthma |
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55 | (8) |
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55 | (1) |
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56 | (1) |
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57 | (4) |
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5.3.4 Supportive Estimand |
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61 | (2) |
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5.4 Example 3: A Confirmatory Trial in Rheumatoid Arthritis |
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63 | (8) |
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63 | (1) |
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64 | (1) |
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5.4.3 Estimand for RA Study Design 1 |
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65 | (4) |
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5.4.4 Estimand 2 for RA Study Design 2 |
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69 | (2) |
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71 | (2) |
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6 Causal Inference and Estimands |
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73 | (16) |
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73 | (1) |
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6.2 Causal Framework for Estimands in Clinical Trials |
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74 | (2) |
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6.2.1 Defining Potential Outcomes |
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74 | (1) |
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6.2.2 Counterfactual Outcomes and Potential Outcomes |
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75 | (1) |
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6.3 Using Potential Outcomes to Define Estimands |
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76 | (7) |
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76 | (3) |
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6.3.2 Specifying Treatment Changes |
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79 | (4) |
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6.4 Examples of Defining Estimands in the Potential Outcome Framework |
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83 | (5) |
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83 | (1) |
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6.4.2 Treatment Policy Strategy |
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83 | (1) |
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84 | (1) |
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6.4.4 Hypothetical Strategy |
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84 | (1) |
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6.4.5 Principal Stratification Strategy |
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85 | (1) |
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6.4.6 While-on-Treatment Strategy |
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85 | (1) |
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6.4.7 Scenarios with Dynamic Treatment Regimens |
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86 | (1) |
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6.4.8 Treatment of Missing Data |
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87 | (1) |
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88 | (1) |
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7 Putting the Principles into Practice |
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89 | (8) |
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89 | (1) |
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90 | (7) |
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Section III Estimators and Sensitivity |
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97 | (2) |
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9 Modeling Considerations |
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99 | (12) |
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99 | (1) |
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9.2 Longitudinal Analyses |
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99 | (9) |
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9.2.1 Choice of Dependent Variable and Statistical Test |
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99 | (2) |
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9.2.2 Modeling Covariance (Correlation) |
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101 | (1) |
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9.2.3 Modeling Means Over Time |
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102 | (2) |
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9.2.4 Accounting for Covariates |
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104 | (1) |
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105 | (2) |
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9.2.6 Model Checking and Verification |
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107 | (1) |
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108 | (3) |
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10 Overview of Analyses for Composite Intercurrent Event Strategies |
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111 | (6) |
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111 | (1) |
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111 | (2) |
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10.3 Rank-Based and Related Methods |
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113 | (2) |
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115 | (2) |
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11 Overview of Analyses for Hypothetical Intercurrent Event Strategies |
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117 | (10) |
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117 | (1) |
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11.2 Estimators for What Would Have Happened in the Absence of Relevant Intercurrent Events |
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118 | (4) |
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118 | (1) |
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11.2.2 Likelihood-Based Analyses |
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119 | (1) |
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11.2.3 Multiple Imputation |
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120 | (1) |
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11.2.4 Inverse Probability Weighting |
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121 | (1) |
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11.2.5 Considerations for Categorical and Time-to-Event Data |
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122 | (1) |
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11.3 Estimators for Treatment Policies That Were Not Included in the Trial or Not Followed |
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122 | (3) |
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122 | (1) |
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11.3.2 Reference-Based Approaches Using Multiple Imputation |
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123 | (1) |
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11.3.3 Considerations for Categorical and Time-to-Event Data |
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124 | (1) |
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11.3.4 Likelihood and Bayesian Approaches to Reference-Based Imputation |
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125 | (1) |
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125 | (2) |
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12 Overview of Analyses for Principal Stratification Intercurrent Event Strategies |
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127 | (4) |
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127 | (1) |
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128 | (2) |
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130 | (1) |
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13 Overview of Analyses for While-on-Treatment Intercurrent Event Strategies |
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131 | (2) |
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14 Overview of Analyses for Treatment Policy Intercurrent Event Strategies |
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133 | (2) |
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135 | (8) |
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135 | (1) |
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135 | (2) |
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15.3 Missing Data Mechanisms |
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137 | (2) |
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15.3.1 General Considerations |
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137 | (1) |
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15.3.2 Considerations for Time-to-Event Analyses |
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138 | (1) |
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15.4 Analytic Considerations |
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139 | (2) |
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15.4.1 General Considerations |
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139 | (1) |
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15.4.2 Considerations When Changing Treatment Is Possible |
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140 | (1) |
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15.5 Inclusive and Restrictive Modeling Approaches |
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141 | (1) |
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142 | (1) |
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143 | (10) |
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16.1 General Considerations |
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143 | (1) |
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16.2 Supplementary Analyses |
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144 | (1) |
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16.3 Assessing Sensitivity to Missing Data Assumptions |
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145 | (2) |
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145 | (1) |
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16.3.2 Assessing Sensitivity to Departures from MAR |
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146 | (1) |
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16.4 Sensitivity to Methods of Accounting for Intercurrent Events |
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147 | (3) |
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147 | (1) |
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16.4.2 Sensitivity Analyses for Hypothetical Strategies |
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148 | (1) |
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16.4.3 Sensitivity Analyses for Composite Strategies |
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148 | (1) |
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16.4.4 Sensitivity Analyses for Principal Stratification Strategies |
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149 | (1) |
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16.4.5 Sensitivity Analyses for While-on-Treatment Strategies |
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149 | (1) |
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16.4.6 Sensitivity Analyses for Treatment Policy Strategies |
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150 | (1) |
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150 | (3) |
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Section IV Technical Details on Selected Analyses |
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153 | (8) |
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153 | (1) |
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17.2 Details of Example Data Set |
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153 | (8) |
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153 | (1) |
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17.2.2 Data Set with Dropout |
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154 | (7) |
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18 Direct Maximum Likelihood |
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161 | (10) |
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161 | (1) |
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18.2 Technical Details of Likelihood Estimation for Repeated Measures |
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161 | (2) |
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18.3 Factoring the Likelihood Function for Ignorability |
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163 | (3) |
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166 | (3) |
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169 | (1) |
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170 | (1) |
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171 | (30) |
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171 | (1) |
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172 | (5) |
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19.3 Example -- Implementing MI |
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177 | (8) |
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177 | (2) |
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179 | (3) |
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182 | (1) |
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183 | (1) |
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19.3.5 Accounting for Non-monotone Missingness |
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184 | (1) |
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19.4 Situations Where MI Is Particularly Useful |
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185 | (3) |
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185 | (1) |
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19.4.2 Scenarios Where Direct Likelihood Methods Are Difficult to Implement or Not Available |
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185 | (1) |
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19.4.3 Exploiting Separate Steps for Imputation and Analysis |
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186 | (1) |
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19.4.4 Sensitivity Analysis |
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187 | (1) |
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19.5 Example -- Using MI to Impute Covariates |
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188 | (2) |
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188 | (1) |
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188 | (2) |
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19.6 Examples -- Using Inclusive Models in MI |
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190 | (4) |
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190 | (1) |
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191 | (3) |
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19.7 MI for Categorical Outcomes |
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194 | (1) |
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194 | (5) |
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199 | (2) |
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20 Inverse Probability Weighted Generalized Estimated Equations |
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201 | (14) |
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201 | (1) |
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20.2 Technical Details -- Generalized Estimating Equations |
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201 | (2) |
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20.3 Technical Details -- Inverse Probability Weighting |
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203 | (6) |
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20.3.1 General Considerations |
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203 | (4) |
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20.3.2 Specific Implementations |
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207 | (2) |
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209 | (2) |
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211 | (2) |
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213 | (2) |
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215 | (14) |
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215 | (1) |
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216 | (3) |
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21.3 Specific Implementations |
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219 | (3) |
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222 | (2) |
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224 | (2) |
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226 | (3) |
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22 Reference-Based Imputation |
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229 | (20) |
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229 | (1) |
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22.2 Multiple Imputation-Based Approach |
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229 | (6) |
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231 | (1) |
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22.2.2 Copy Increment from Reference |
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232 | (1) |
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233 | (1) |
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234 | (1) |
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235 | (1) |
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22.3 Group Mean Imputation Using a Likelihood-Based Approach |
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235 | (4) |
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22.4 Bayesian-Based Approach |
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239 | (3) |
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22.5 Considerations for the Variance of Reference-Based Estimators |
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242 | (4) |
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246 | (1) |
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247 | (2) |
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248 | (1) |
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249 | (6) |
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249 | (1) |
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249 | (2) |
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251 | (2) |
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253 | (1) |
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254 | (1) |
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24 Overview of Principal Stratification Methods |
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255 | (18) |
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255 | (1) |
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24.2 Principal Stratification Based on Intercurrent Events |
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255 | (3) |
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24.3 Principal Stratification Based on Post-randomization Treatment |
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258 | (1) |
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24.4 Principal Stratification Based on the Post-randomization Outcomes |
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259 | (5) |
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259 | (1) |
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24.4.2 The Case of a Binary Outcome |
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260 | (2) |
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24.4.3 The Case of a Continuous Outcome |
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262 | (2) |
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24.5 Utilizing Baseline Covariates |
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264 | (2) |
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264 | (1) |
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24.5.2 Predicted Counterfactual Response |
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265 | (1) |
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24.5.3 Strata Propensity Weighted Estimator |
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266 | (1) |
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24.6 Implementing Principal Stratification Strategy via Imputation |
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266 | (2) |
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24.7 Approximation of Survivor Average Causal Effect |
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268 | (2) |
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270 | (3) |
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Section V Case Studies: Detailed Analytic Examples |
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25 Analytic Case Study of Depression Clinical Trials |
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273 | (1) |
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273 | (2) |
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26 Analytic Case Study Based on the ACTG |
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275 | (6) |
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281 | (1) |
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281 | (1) |
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282 | (2) |
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26.3 Estimands and Estimators for the Case Study |
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284 | (25) |
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284 | (1) |
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26.3.2 Estimands for the Continuous Endpoint of Change from Baseline in CD4 |
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284 | (8) |
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26.3.3 Estimands Based on the Time-to-Event Outcomes |
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292 | (7) |
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299 | (10) |
Glossary |
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309 | (2) |
Index |
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311 | |