Facts Versus Fears

Summary of “Facts and Fears: Understanding Perceived Risk”, a study of risk perception conducted by Slovic, Fischhoff, and Lichtenstein.

Perception of risk refers to the acceptance that there is in fact a risk. Acceptability of risk refers to how much the risk can be tolerated; to what level it should be controlled.

INVOLUNTARINESS

New research suggests that the accepted views on catastrophic loss may need to be revised.  A current, popular view, based on a hypothesis forwarded by Starr (1969),  says that people tend to demand stricter standards against hazards brought on by involuntary risks (involuntary risks are risks one does not take by choice).  This hypothesis says that risks that are involuntary are perceived to be less tolerable. 

Slovic, et. al's study did not intentionally seek to address Starr's hypothesis, but the findings provided an interesting test of it.  Their new study seems to suggest that in addition to voluntariness, a host of other factors such as knowledge, controllability, etc. need to be factored into risk standards. 

Their study further tends to the notion that it may not be involuntariness per se that drive the call for stricter results, but other conditions closely associated with involuntariness, such as catastrophic results.  Involuntary hazards tend to include large-scale catastrophic events such as nuclear power, terrorism, bio-chemical threats.

Levels of acceptability of risk correlates positively with perceived benefits of the risk, in fact more strongly than voluntariness.

CATASTROPHIC POTENTIAL

The study suggests that it is the (perceived) potential for massive loss,  rather than involuntariness, that could be the driving force to risk perception and acceptability.

CONCLUSIONS

1. Perceived risk is quantifiable and predictable.
2. Groups of people differ systematically in their perceptions
3. People make mistakes in judging risks.
4. Experts are also susceptible to bias.
5. The various modes of death possible from risks do not seem to have a significant impact on public vs. expert perceptions of risk (???)
6. The higher the perceived current level of risk, the larger the required adjustment needed to bring the risk down to acceptable levels.
7. The perceived potential for catastrophic loss of life is one of the most important risk characteristics (more so than involuntariness)
8. Evidence does not remove disagreements. Definitive evidence is rare. All other forms of evidence can be skewed to pre-conceived positions.

Further conclusions. The authors conclude that the public can make gross mistakes in perceptions of risk, but then so do experts, so public opinion ought not to be excluded from risk decisions.  It is much better to involve the public in risk matters for the purpose of increasing their knowledge in the longer term and also because their cooperation is needed for risk management undertakings to succeed.