Description
Book SynopsisA one-of-a-kind resource on identifying and dealing with bias in statistical research on causal effects Do cell phones cause cancer? Can a new curriculum increase student achievement? Determining what the real causes of such problems are, and how powerful their effects may be, are central issues in research across various fields of study. Some researchers are highly skeptical of drawing causal conclusions except in tightly controlled randomized experiments, while others discount the threats posed by different sources of bias, even in less rigorous observational studies. Bias and Causation presents a complete treatment of the subject, organizing and clarifying the diverse types of biases into a conceptual framework. The book treats various sources of bias in comparative studiesboth randomized and observationaland offers guidance on how they should be addressed by researchers.
Utilizing a relatively simple mathematical approach, the author develops a theory of bias that
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"The book combines a useful synthesis of the literature with an original working through of issues related to bias and causal inference. Anyone with a sustained interest in this topic will find the book worth reading." (Journal of Educational and Behavioral Statistics, May 2012)
"...the book provides a unified framework for understanding issues of causal inference discussed differently across disciplines...the book will also be of substantial interest to methodologically minded readers working within specific disciplines but interested in methodological literature from other disciplines." (Journal of Educational and Behavioral Statistics, May 2012)
"The book covers almost all the relevant biases that can be present when designing and analyzing treatment effects in comparative studies." (Journal of Biopharmaceutical Statistics, January 2011)"A consultant who specializes in applying statistics to various business and legal issues, Weisberg explains approaches to bias and causal inference, a realm statisticians have avoided until recently because it requires intuitive skills beyond the pale of mathematics. He writes for practicing researchers and methodologists and for students with a reasonably solid grounding in basic statistics and research methods." (SciTech Book News, December 2010)
Table of ContentsPreface xi
1. What Is Bias? 1
1.1 Apples and Oranges, 2
1.2 Statistics vs. Causation, 3
1.3 Bias in the Real World, 6
Guidepost 1, 23
2. Causality and Comparative Studies 24
2.1 Bias and Causation, 24
2.2 Causality and Counterfactuals, 26
2.3 Why Counterfactuals? 32
2.4 Causal Effects, 33
2.5 Empirical Effects, 38
Guidepost 2, 46
3. Estimating Causal Effects 47
3.1 External Validity, 48
3.2 Measures of Empirical Effects, 50
3.3 Difference of Means, 52
3.4 Risk Difference and Risk Ratio, 55
3.5 Potential Outcomes, 57
3.6 Time-Dependent Outcomes, 60
3.7 Intermediate Variables, 63
3.8 Measurement of Exposure, 64
3.9 Measurement of the Outcome Value, 68
3.10 Confounding Bias, 70
Guidepost 3, 71
4. Varieties of Bias 72
4.1 Research Designs and Bias, 73
4.2 Bias in Biomedical Research, 81
4.3 Bias in Social Science Research, 85
4.4 Sources of Bias: A Proposed Taxonomy, 90
Guidepost 4, 92
5. Selection Bias 93
5.1 Selection Processes and Bias, 93
5.2 Traditional Selection Model: Dichotomous Outcome, 100
5.3 Causal Selection Model: Dichotomous Outcome, 102
5.4 Randomized Experiments, 104
5.5 Observational Cohort Studies, 108
5.6 Traditional Selection Model: Numerical Outcome, 111
5.7 Causal Selection Model: Numerical Outcome, 114
Guidepost 5, 121
Appendix, 122
6. Confounding: An Enigma? 126
6.1 What is the Real Problem? 127
6.2 Confounding and Extraneous Causes, 127
6.3 Confounding and Statistical Control, 131
6.4 Confounding and Comparability, 137
6.5 Confounding and the Assignment Mechanism, 139
6.6 Confounding and Model Specifi cation, 141
Guidepost 6, 144
7. Confounding: Essence, Correction, and Detection 145
7.1 Essence: The Nature of Confounding, 146
7.2 Correction: Statistical Control for Confounding, 172
7.3 Detection: Adequacy of Statistical Adjustment, 180
Guidepost 7, 191
Appendix, 192
8. Intermediate Causal Factors 195
8.1 Direct and Indirect Effects, 195
8.2 Principal Stratifi cation, 200
8.3 Noncompliance, 209
8.4 Attrition, 214
Guidepost 8, 215
9. Information Bias 217
9.1 Basic Concepts, 218
9.2 Classical Measurement Model: Dichotomous Outcome, 223
9.3 Causal Measurement Model: Dichotomous Outcome, 230
9.4 Classical Measurement Model: Numerical Outcome, 239
9.5 Causal Measurement Model: Numerical Outcome, 242
9.6 Covariates Measured with Error, 246
Guidepost 9, 250
10. Sources of Bias 252
10.1 Sampling, 254
10.2 Assignment, 260
10.3 Adherence, 266
10.4 Exposure Ascertainment, 269
10.5 Outcome Measurement, 273
Guidepost 10, 277
11. Contending with Bias 279
11.1 Conventional Solutions, 280
11.2 Standard Statistical Paradigm, 286
11.3 Toward a Broader Perspective, 288
11.4 Real-World Bias Revisited, 293
11.5 Statistics and Causation, 303
Glossary 309
Bibliography 321
Index 340
