Preface |
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xi | |
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1 | (12) |
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1 | (1) |
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1 | (1) |
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2 | (1) |
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2 | (2) |
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Types of quality of life measures |
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4 | (6) |
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Why measure quality of life? |
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10 | (1) |
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11 | (2) |
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Measuring quality of life |
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13 | (18) |
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13 | (1) |
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13 | (1) |
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Principles of measurement scales |
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13 | (2) |
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13 | (1) |
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Constructs and latent variables |
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14 | (1) |
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Indicator and causal variables |
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15 | (1) |
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15 | (1) |
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15 | (1) |
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Why do we need to worry about the distinction between indicator and causal items? |
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16 | (1) |
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Single-item versus multi-item scales |
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16 | (1) |
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The traditional psychometric model |
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16 | (1) |
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Psychometrics and QoL scales |
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17 | (1) |
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17 | (1) |
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Traditional scales versus IRT |
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18 | (1) |
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18 | (1) |
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Measuring quality of life: Indicator or causal items |
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19 | (1) |
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Developing and testing questionnaires |
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19 | (11) |
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Specify the research question and define the target population |
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19 | (1) |
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20 | (1) |
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21 | (5) |
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Assess measurement properties |
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26 | (4) |
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30 | (1) |
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30 | (1) |
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Choosing a quality of life measure for your study |
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31 | (24) |
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31 | (1) |
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31 | (1) |
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How to choose between instruments |
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31 | (2) |
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33 | (1) |
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33 | (1) |
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34 | (1) |
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35 | (3) |
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Tests for criterion validity |
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35 | (1) |
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Tests for face and content validity |
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36 | (1) |
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Tests for construct validity |
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36 | (2) |
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38 | (6) |
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Repeatability reliability |
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40 | (1) |
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Graphical methods for assessing reliability between two repeated measurements |
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40 | (2) |
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Internal reliability or internal consistency reliability |
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42 | (2) |
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44 | (5) |
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Floor and ceiling effects |
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44 | (5) |
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49 | (2) |
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51 | (2) |
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Finding quality of life instruments |
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53 | (2) |
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Design and sample size issues: How many subjects do I need for my study? |
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55 | (36) |
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55 | (1) |
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55 | (1) |
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Significance tests, P-values and power |
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56 | (2) |
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Sample sizes for comparison of two independent groups |
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58 | (11) |
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Normally distributed continuous data - comparing two means |
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58 | (3) |
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61 | (1) |
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Comparing two groups with continuous data using non-parametric methods |
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61 | (2) |
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Dichotomous categorical data - comparing two proportions |
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63 | (3) |
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Ordered categorical (ordinal) data |
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66 | (3) |
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Choice of sample size method with quality of life outcomes |
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69 | (1) |
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70 | (3) |
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Paired continuous data - comparison of means |
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70 | (2) |
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Paired binary data - comparison of proportions |
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72 | (1) |
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Equivalence/non-inferiority studies |
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73 | (2) |
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Continuous data - comparing the equivalence of two means |
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74 | (1) |
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Binary data - comparing the equivalence of two proportions |
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75 | (1) |
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Unknown standard deviation and effect size |
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75 | (1) |
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Tips on obtaining the standard deviation |
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76 | (1) |
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Cluster randomized controlled trials |
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76 | (1) |
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77 | (1) |
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77 | (2) |
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Multiple outcomes/endpoints |
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79 | (1) |
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80 | (1) |
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What if we are doing a survey, not a clinical trial? |
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80 | (5) |
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80 | (1) |
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Confidence intervals for estimating the mean QoL of a population |
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81 | (1) |
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Confidence intervals for a proportion |
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82 | (3) |
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Sample sizes for reliability and method comparison studies |
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85 | (1) |
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Post-hoc sample size calculations |
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86 | (1) |
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Conclusion: Usefulness of sample size calculations |
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86 | (1) |
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86 | (5) |
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Reliability and method comparison studies for quality of life measurements |
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91 | (18) |
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91 | (1) |
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91 | (1) |
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Intra-class correlation coefficient |
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92 | (3) |
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94 | (1) |
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Agreement between individual items on a quality of life questionnaire |
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95 | (3) |
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Binary data: Proportion of agreement |
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95 | (1) |
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95 | (1) |
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Ordered categorical data: Weighted kappa |
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96 | (2) |
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Internal consistency and Cronbach's alpha |
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98 | (1) |
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Graphical methods for assessing reliability or agreement between two quality of life measures or assessments |
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99 | (3) |
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102 | (1) |
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102 | (7) |
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102 | (1) |
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103 | (1) |
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Calculation of weighted kappa |
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104 | (1) |
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Calculation of Cronbach's alpha |
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104 | (5) |
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Summarizing, tabulating and graphically displaying quality of life outcomes |
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109 | (24) |
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109 | (1) |
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109 | (1) |
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110 | (6) |
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112 | (1) |
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112 | (2) |
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114 | (2) |
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116 | (1) |
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Describing and summarizing quality of life data |
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116 | (6) |
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117 | (2) |
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119 | (3) |
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Presenting quality of life data and results in tables and graphs |
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122 | (11) |
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Tables for summarizing QoL outcomes |
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122 | (2) |
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Tables for multiple outcome measures |
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124 | (2) |
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Tables and graphs for comparing two groups |
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126 | (3) |
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129 | (4) |
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Cross-sectional analysis of quality of life outcomes |
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133 | (48) |
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133 | (1) |
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133 | (1) |
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Hypothesis testing (using P-values) |
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134 | (3) |
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Estimation (using confidence intervals) |
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137 | (1) |
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Choosing the statistical method |
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138 | (1) |
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Comparison of two independent groups |
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138 | (8) |
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Independent samples t-test for continuous outcome data |
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140 | (4) |
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144 | (2) |
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Comparing more than two groups |
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146 | (4) |
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One-way analysis of variance |
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147 | (3) |
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150 | (1) |
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Two groups of paired observations |
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150 | (7) |
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153 | (4) |
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157 | (1) |
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The relationship between two continuous variables |
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157 | (3) |
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160 | (5) |
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165 | (3) |
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168 | (3) |
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Regression or correlation? |
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171 | (1) |
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Parametric versus non-parametric methods |
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171 | (2) |
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Technical details: Checking the assumptions for a linear regression analysis |
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173 | (8) |
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Randomized controlled trials |
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181 | (36) |
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181 | (1) |
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181 | (1) |
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Randomized controlled trials |
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182 | (1) |
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182 | (1) |
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Pragmatic and explanatory trials |
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182 | (1) |
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Intention-to-treat and per-protocol analyses |
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183 | (3) |
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186 | (1) |
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Comparison of entry characteristics |
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186 | (3) |
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189 | (2) |
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191 | (5) |
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Interpretation of changes/differences in quality of life scores |
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196 | (1) |
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Superiority and equivalence trials |
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197 | (2) |
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Adjusting for other variables |
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199 | (3) |
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Three methods of analysis for pre-test/post-test control group designs |
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202 | (1) |
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203 | (3) |
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206 | (3) |
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Cluster randomized controlled trials |
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209 | (1) |
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210 | (7) |
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Exploring and modelling longitudinal quality of life data |
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217 | (32) |
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217 | (1) |
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217 | (1) |
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Summarizing, tabulating and graphically displaying repeated QoL assessments |
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218 | (4) |
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222 | (1) |
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Response feature analysis - the use of summary measures |
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223 | (6) |
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223 | (4) |
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Acupuncture study - analysis of covariance |
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227 | (2) |
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Modelling of longitudinal data |
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229 | (14) |
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231 | (1) |
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Repeated measures analysis of variance |
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232 | (1) |
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Marginal general linear models - generalized estimating equations |
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232 | (5) |
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237 | (2) |
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Random effects versus marginal modelling |
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239 | (2) |
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Use of marginal and random effects models to analyse data from a cluster RCT |
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241 | (2) |
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243 | (6) |
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Advanced methods for analysing quality of life outcomes |
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249 | (16) |
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249 | (1) |
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249 | (2) |
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251 | (1) |
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Bootstrap methods for confidence interval estimation |
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251 | (4) |
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255 | (2) |
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Comparing two independent groups: Ordinal quality of life measures (with less than 7 categories) |
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257 | (1) |
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Proportional odds or cumulative logit model |
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258 | (1) |
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259 | (1) |
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Stereotype logistic model |
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260 | (4) |
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Conclusions and further reading |
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264 | (1) |
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265 | (12) |
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265 | (1) |
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265 | (1) |
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266 | (1) |
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266 | (1) |
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Economic evaluations alongside a controlled trial |
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267 | (1) |
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Cost-effectiveness analysis |
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267 | (1) |
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Cost-effectiveness ratios |
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268 | (1) |
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Cost-utility analysis and cost-utility ratios |
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269 | (1) |
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Incremental cost per QALY |
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270 | (2) |
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The problem of negative (and positive) incremental cost-effectiveness ratios |
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272 | (1) |
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Cost-effectiveness acceptability curves |
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273 | (2) |
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275 | (2) |
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277 | (20) |
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277 | (1) |
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277 | (1) |
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278 | (4) |
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Is a meta-analysis appropriate? |
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279 | (1) |
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Combining the results of different studies |
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279 | (1) |
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Choosing the appropriate statistical method |
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280 | (2) |
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Statistical methods in meta-analysis |
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282 | (11) |
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The choice of effect measure: What outcome measures am I combining? |
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282 | (1) |
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Model choice: fixed or random? |
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283 | (2) |
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285 | (1) |
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285 | (2) |
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287 | (2) |
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289 | (1) |
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289 | (4) |
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293 | (1) |
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294 | (1) |
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295 | (2) |
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297 | (22) |
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297 | (1) |
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297 | (13) |
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Why do missing data matter? |
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297 | (1) |
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Methods for missing items within a form |
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298 | (2) |
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Methods for missing forms |
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300 | (8) |
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The regulator's view on statistical considerations for patient-level missing data |
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308 | (1) |
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Conclusions and further reading on missing QoL data |
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309 | (1) |
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Multiplicity, multi-dimensionality and multiple quality of life outcomes |
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310 | (4) |
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Which multiple comparison procedure to use? |
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312 | (2) |
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Guidelines for reporting quality of life studies |
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314 | (5) |
Solutions to exercises |
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319 | (16) |
Appendix A: Examples of questionnaires |
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335 | (10) |
Appendix B: Statistical tables |
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345 | (6) |
References |
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351 | (10) |
Index |
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361 | |