1. Why do some people under-estimate risk?

2. Hazard risk Hazard Probability
The chance of a hazard event causing great damage (ie becoming a disaster).
Hazard Probability
The chance of a hazard event occurring. Note, magnitude, frequency & location are required . Eg, The chance of a magnitude 8 earthquake occurring once in North America.

3. Some people under-estimate risk if:
They feel they have some control over the event eg have a car to escape in, or they can ski/mountaineer/swim/surf.
They lack information about likely hazards.
The media under-reports or else does not report events accurately.

4. Some people under-estimate risk if:
The last event happened a very long time before.
They believe, incorrectly, that technology can manage the hazard.
They do not identify indirect links. Eg an earthquake may lead to a fall in tourist visitors.

5. Some people under-estimate risk if:
They are hold fundamentalist religious beliefs.
They have more pressing matters eg are unemployed and need a job.
There is civil/political unrest.
The event takes a long time to unfold (frog in hot water).

6. Some people under-estimate risk if:
The event occurs frequently eg minor tremors in earthquake zones.
The event usually leads to few deaths.
Deaths appear random in space and time eg lung cancer.
Victims are statistical eg cigarette smokers in general.

7. Some people over-estimate risk if
They have no control over it (eg a radiation leak).
There is a direct and immediate impact.
They perceive high death rates resulting (Ebola, Mers, Sars H1N1).

8. Some people over-estimate risk if:
Death rates are often high.
Deaths are grouped in space and time.
Victims are identifiable.
Processes are not well-understood (nuclear reactions).

9. Some people over-estimate risk if
Hazards cannot be controlled eg Hurricanes & earthquakes.
Hazards are unfamiliar eg Ebola, tsunami.
People lack belief in authority figures (eg scientists and members of the government)