18 Factors of Risk Perception

In Dan Gardner’s excellent Risk, he lists psychologist Paul Slovic‘s list of 18 factors that influence how we judge the severity of risk:

  1. Catastrophic Potential If fatalities would occur in large numbers in a single event — instead of in small numbers dispersed over time — our perception of risk rises.
  2. Familiarity Unfamiliar or novel risks make us worry more.
  3. Understanding If we believe that how an activity or technology works is not well understood, our sense of risk goes up.
  4. Personal Control If we feel the potential for harm is beyond our control — like a passenger in an airplane — we worry more than if we feel in control — the driver of a car.
  5. Voluntariness If we don’t choose to engage the risk, it feels more threatening.
  6. Children It’s much worse if kids are involved.
  7. Future Generations If the risk threatens future generations, we worry more.
  8. Victim Identity Identifiable victims rather than statistical abstractions make the sense of risk rise.
  9. Dread If the effects generate fear, the sense of risk rises.
  10. Trust If the institutions involved are not trusted, risk rises.
  11. Media Attention More media means more worry.
  12. Accident History Bad events in the past boost the sense of risk.
  13. Equity If the benefits go to some and the dangers to others, we raise the risk ranking.
  14. Benefits If the benefits of the activity or technology are not clear, it is judged to be riskier.
  15. Reversibility If the effects of something going wrong cannot be reversed, risk rises.
  16. Personal Risk If it endangers me, it’s riskier.
  17. Origin Man-made risks are riskier than those of natural origin.
  18. Timing More immediate threats loom larger while those in the future tend to be discounted.

For more on risk perception, you can do worse than peruse the Wikipedia entry.