Friday, September 26, 2008

Relative Risk v. Perceived Risk

I am still thinking about the idea of relative v. perceived risk. Many outdoor activities are viewed as risky. For example, downhill skiing appears to have a higher risk factor than walking in a city park. However, depending on the time of day and the location of the park, the walk in the park might be much more of a risk that skiing. There are some activities which, by their nature, are high risk activities. For example, free climbing without protection, is more hazardes than with protection. My issue with the Scouting Magazine article for October, 2008 "Don't get sick on the trail" is the use of an unexplained statistic to increase the reader's perceived risk of an otherwise safe activity. It seems to me that ultimately, the real measure of any activity's risk is the mortality rate per number of participants. The use of mortality rates eliminates the issue that in a rather benign activity, like hiking, the injuries are likely to be minor, whereas a crash in bobsled could be a lot more serious.

Authors Richard J Zeckhauser and W. Kip Viscusi give the following observation:

"Society's system for managing risks to life and limb is deeply flawed. We overreact to some risks and virtually ignor others. Often too much wight is placed on risks of low probability but high salience (such as those posed by trace carcinogens or terrorist action); risks of commission rather than omission; and risks, scuh as those associated with frontier technologies, whose magnitue is difficult to estimate. Too little effort is spent ameliorating voluntary risks, such as those involving automobiles and diet. When the bearers of risk do not share in the costs of reduction, moreover, extravagance is likely. " See Simon, Julian Lincoln. The State of Humanity. Oxford, UK: Blackwell in association with the Cato Institute, 1995.

It is interesting to note the following Centers for Disease Control and Prevention, Mortality Data (See http://www.cdc.gov/nchs/about/otheract/injury/injury_mortality.htm ):

"In 2002, the 10 leading causes of death were (in rank order) Diseases of heart; Malignant neoplasms; Cerebrovascular diseases; Chronic lower respiratory diseases; Accidents (unintentional injuries); Diabetes mellitus; Influenza and pneumonia; Alzheimer’s disease; Nephritis, nephrotic syndrome and nephrosis; and Septicemia and accounted for about 79 percent of all deaths occurring in the United States."

The CDCP indicates that in 2002, accidents comprised only 4.4% of all deaths in the U.S. However, the death rate for males between the ages of the 10 and 40 is as high as 50% from accidents. Essentially, what that means is that young men are not likely to die of anything else.

Perhaps, it would be a good idea to weigh the benefits of walking and hiking as compared to the risks of heart disease. When obesity is a national epidemic, it not appropriate to give overemphasis to the risks involved in walking around in the sunshine.


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