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Modified December 10th 2004

Richard Wilson was a founder member of the Society for Risk Analysis and is a holder of their Distinguished achievement award.  He helped start, and is an affilate of,  the Harvard Center for Risk Analysis.  The Center has publshed 4 important books:

2nd edition

Richard Wilson and Edmund A.C. Crouch

Published by Harvard Center for Risk Analysis
Distributed by:

Harvard University Press
79 Garden Street
Cambridge, Massachusetts 02138

Telephone:  617-495-2600
FAX: 617 496 2550

E mail:
Ropeik D and Gray G
Harvard Center for Risk Analysis

A practical guide for deciding what's really safe and what's really dangerous in the world around you.
Houghton Mifflin Company;


Kimberly M. Thompson

Associate Professor of Risk Analysis and Decision Science
Department of Health Policy and Management
Harvard School of Public Health

Risk in Perspective
Insight and Humor in the Age of Risk Management

and this
Peter J. Neumann
Using Cost Effectiveness Analysis to improve Health Care
opportunities and barriers

Oxford University Press (2005)

Table of Contents of Risk Benefit Analysis
 Preface                                                 xi

1. Introduction: Perspective on Risk                     1

Perception is Crucial                                    3
Definition of Risk                                       7
Risk Changes as Events Unfold                            9
Measures of Risk 10
Different Measures Can Lead to Different Decisions      13
Absolute or Incremental Risk                            16
Defining the System Boundary                            17
Layout of the Book                                      20

2. Methods of Risk Calculation and Estimation           25
Evaluation of Historical Risks                          27
Historical Risk Plus a Model                            33
New Risks: (1)Factorization of an Engineering System
with an Event Tree                                      38
New Risks: (2) of Epidemiology and Its Ambiguities      45
Risks of Doses Less than Background: The Linear
Default                                                 47
Beneficial Effects and Hormesis                         51
New Risks: (3) The Use of Animal Data to Estimate Risks
to Humans                                               53
Probability of Causation                                60
Elicitation of Expert Opinion                           62
Exposure and Dose Estimation                            63
The Risk of a System the Impact Pathway Approach        68
Risk of the Impossible                                  71
Large and Immeasurable Risks                            72
The Chimera of Zero Risk Predictable but Irrelevant     73

3. Uncertainty and Variability                          75
Risk Implies Uncertainty                                75
Different Types of Uncertainty                          77
As Risk Changes with Time, So Does Uncertainty          78
Stochastic Uncertainties                                78
Variability vs. Uncertainty                             79
Uncertainty vs. Error                                   82
Uncertainty in Cancer Risk Assessment                   84
Monte Carlo Models                                      85
Model Uncertainty                                       86
Uncertainty in Expert Elicitation                       88
Overconfidence in Uncertainty Estimates                 88

4. Perception of Risks                                  91
Tverskys Analyses                                       92
Other Attributes and Dimensions                         94
Managers and Decision Makers Consider Public Perception 99
Comparing Risks (Risk-Risk Comparisons)                105
Comparing Risks for the Same Benefit (Cost
Effectiveness)                                         112
Expression of Risks                                    113
Public Misconceptions                                  115
Common Public Misconceptions                           115
Recipe for Communication                               120

5. Formal Comparison of Risk and Benefit               123
Distributional Inequity                                125
Issues in Deriving the Constants                       126
Discounting                                            131
Approximations and Simplified Schemes                  132

6. Risk Management: Managing and Reducing Risks        135
We Calculate Risks in Order to Reduce Them             136
Schemes for Analyzing Risk Management Options          136
Criteria for Risk Management                           140
The Ban or Taboo                                       143
Best Available Control Technology                      144
Risk-Cost-Benefit Analysis                             146
Regulation on Upper Limit of Risk                      146
Risk versus Certainty of Information                   148
The De Minimis Risk                                    148
Regulations of the U.S. EPA                            149
Probability of Causation                               150
Management by Avoiding Precursors                      154
Risk vs.Certainty of Information                       155
Asbestos and Dioxin                                    157
Reducing Risk by Technological Improvement             159
Radiation Protection                                   160
Economic Incentives                                    161
The Multiple Uses of a Risk Assessment                 162
Use of Comparisons to Guide a Manager                  162
Safety Culture and the Importance of Incentives        163
Congress as the Filter for Societal Values             164
The Dual Role of the Courts                            165

7. Lists of Risks                                      169
Some Examples of Risk Calculations                     170
The Risk (of Death) in Living                          170
Life Expectancy                                        172
A Selection of Risks: Historically Calculated          173
Time (or Action)to Reach One in a Million Risk         183
Loss of Life Expectancy (LOLE)                         185
A Partial List of Catastrophes                         188
Amounts Paid to Avert Deaths                           190
Variation and Uncertainties                            197
Detailed Discussions of Some Risks                     199

8. Bibliography                                        239
Books                                                  239
Journals                                               251
Websites                                               252
Specific References                                    255

Appendix 1: Some Famous Quotations                     277

Appendix 2: Application of EPAs Hazardous Waste
Identification Rule                                    283
1.Variability                                          284
2.Uncertainty                                          285
3.Legislative Mandate and its Interpretation           286
4.Precise Definitions                                  289

Appendix 3: Procedure Used for Age Adjustment by NCHS  299

Appendix 4: Are Mushrooms Safe to Eat, or Should They
Be Considered Toxic Waste?                             301
The Problem                                            301
Materials and Methods                                  301
Results                                                302
Implications                                           303
Modifying Comments                                     305

Appendix 5:Evaluating the Lung-Cancer Risks Due to
Smoking, Exposure to Asbestos, and Their Combination   307
Smoking                                                308
Asbestos                                               316
Assigning Causation of Lung Cancer to Smoking and
Asbestos the Logic of the Approach                     321
Interaction between Smoking and Cigarettes              324


Risk/Benefit Analysis
, by Richard Wilson and Edmund Crouch, provides an inclusive and authoritative review of the methodology for assessing risks to human health.  In a style intelligible to a broad readership,  the book shows how such risks are defined, measured, and estimated; how variability and uncertainty enter into such risk assessments and must be dealt with; how perceptions of a risk may vary among different individuals and groups; and how differences in the perception of a risk and the corresponding risk/benefit relationship can shape the risk-management decision. To amplify its discussion of these topics, the book is replete with illustrative examples, helpful lists of comparative risks, explanatory appendices, and an extensive bibliography. The volume should  therefore serve as a uniquely valuable source book and primer for students, professionals, and all others interested in risk/benefit analysis.

Dr. Arthur Upton
A distinguished physician, was the Director of the National Cancer Institute in the late 1970s.

This is by far the best book yet available on risk benefit analysis. Based on long study and personal field experience (e.g. Chernobyl) the authors have covered the entire spectrum of risk-benefit analysis in authoritative fashion. They have assembled a remarkable array of pertinent data and used them to illustrate their analyses and these data are themselves fascinating. They have successfully bridged the huge gap between often wildly subjective public perceptions of risk and the now possible objective analyses of these risks. This book is not only required reading for anyone involved with risk assessment and management but also, and more important, it can be highly recommended to the interested public.

Dr. Allan Bromley
Sterling Professor of the Sciences and
Dean of Engineering, Yale University
The Assistant for Science and Technology
To President George Bush 1989-1993

Managing risk in a free society is an extremely difficult task.  No one knows more about how to analyze risk and balance it against the benefits to society than Dick Wilson and Edmund Crouch .  Anyone interested in this subject and who wants to know more about it, should read this book.  You will come away from that effort with a more balanced view of risk and more toleration for processes whereby we analyze risk and balance it against the good things we all want.

William D. Ruckelshaus
William Doyle Ruckelshaus was the first EPA Agency Administrator,  1970 to 1973 and again from 1983-1985. He was briefly Acting FBI Director, and Deputy Attorney General.  He is now a principal in Madrona Investment Group, in Seattle.

since July 2nd, 2003