The subject of this volume--uncertainties in risk assessment and
management--reflects an important theme in health, safety, and environ-
mental decision making. MOst technological hazards are characterized by
substantial uncertainty. Recent examples include nuclear waste disposal,
acid rain, asbestos in schools, carcinogens in food, and hazardous
waste. realing with such uncertainty is arguably the most difficult and
challeng- ing task facing risk assessors and managers today. Four
primary sources of uncertainty in risk assessment and management can be
identified: (1) uncertainties about definitions; (2) uncertainties about
scientific facts; (3) uncertainties about risk perceptions and atti-
tudes; and (4) uncertainties about values. Uncertainties about
definitions derive primarily from disagreements about the meaning and
interpretation of key concepts, such as probability. Uncertainties about
scientific facts derive primarily from disagreements about failure
modes, the probability and magnitude of adverse health or environmental
consequences, cause and effect relationships, dose-response
relationships, and exposure patterns. Uncertainties about risk
perceptions and attitudes derive primarily from disagreements about what
constitutes a significant or acceptable level of risk. Uncertainties
about values derive primarily from disagreements about the desirability
or worth of alternative risk management actions or conse- quences. The
papers in this volume address each of these sources of uncertainty from
a variety of perspectives. Reflecting the broad scope of risk assess-
ment and risk management research, the papers include contributions from
safety engineers, epidemiologists, toxicologists, chemists,
biostatisticians, biologists, decision analysts, economists,
psychologists, political scien- tists, sociologists, ethicists, and
lawyers.
