Perception of the consequence term

The same way of looking at risk can be seen in everyday life. In a typical large American city, around 500 people die each year in traffic accidents. Although many efforts are made to reduce this fatality rate, the fact remains that this loss of life is perceived as a necessary component of modem life hence, there is little outrage on the part of the public. Yet, if an airplane carrying 500 people crashed at that same city s airport every year, there would be an outcry. The fatality rate is the same in each case, i.e., 500 deaths per city per year. The difference between the two risks is a perception rooted in feelings and values. 

To accommodate the difference in perception regarding risk. Equation (1.1) can be modified so as to take the form of Equation (1.2). 

Equation (1.2) shows that the contribution of the consequence term has been raised by the exponent n, where 1. In other words, high-consequence/low-fre-quency accidents are assigned a higher perceived risk value than low-conse-quence/high-frequency accidents. 

Since the variable n represents subjective feelings it is impossible to assign it an objective value. However, if a value of say 1.5 is given to n then Equation (1.2) for the two scenarios just discussed—the airplane crash and the highway fatalities— becomes Equations (1.3) and (1.4), respectively. 

The 500 airplane fatalities are perceived as being equivalent to over 11,000 automobile fatalities, i.e., the apparent risk of an airplane crash is 17.3 times greater than for the multiple automobile fatalities. 

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