Lesson 2 Background Notes

The Debate About Risk

The concept of risk is enormously complex. Our understanding of the complexity of the concept has increased as specialists from different disciplines have investigated what we mean when we say that a technology or activity is risky. Initially, engineering safety studies of nuclear reactors, which strongly influenced the emergence of modern-day risk analysis, defined risk in probabilistic terms. They defined risk as the product of the probability and consequences of an adverse event, and developed and compared quantitative estimates of the risk (i.e., probability) of dying from various technologies. This definition of risk began to change as new findings appeared.

Psychologists who subsequently studied the individual’s response to perceived risk discovered that the people whom they interviewed did not rate risk in the same way as experts in the field of probabilistic risk analysis. Experts’ rating of various activities and technologies correlated highly with statistical frequencies of death; laypersons’ judgments incorporated considerations other than annual fatalities. Factors such as whether the technology could have catastrophic consequences or whether the technology was unfamiliar appeared to influence the layperson’s judgment of risk.

More recently, anthropologists and sociologists have pointed out that the issue of risk is more complex than studying people’s responses. They emphasize that social factors affect the way we select risk and that these factors affect the judgment of both experts and members of the public. Thus, factors such as our educational, family, or occupational background affect our judgment of which dangers we are afraid of, which risks should be taken, and who should take them. These factors affect our judgment of what we need to examine in conducting risk analysis and our evaluation of the consequences.

As a result of these various studies, we are beginning to realize that making decisions about risk is much more complex than developing probabilistic estimates. The kinds of problems that we are facing are what Alvin Weinberg* has called transscientific problems—problems that cannot be answered by science because they involve questions of values as well as facts. A primary purpose of this classroom activity on risk is to facilitate students’ awareness of the complexity of the risk concept and recognition that there is no one best factual answer to questions about risk. Hopefully, this unit will stimulate discussion of ways in which, in a democratic society, we can make decisions about risk.

*Former Director of the Institute for Energy Analysis of the Oak Ridge Associated Universities, Oak Ridge, TN.