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Health Risk Policy Analysis - Precautionary Principle

Current decision making in the field of environmental and public health risk management is generally evidence-based, which is appropriate and valuable when sufficient scientific information is available. However, in view of rapid advances in technologies with potential adverse effects of these applications on the environment and human health, policy decisions are sometimes needed before additional knowledge can be obtained. In response to this need, a more precautionary approach has emerged as a new paradigm. One of many definitions of the precautionary principle follows:

“The Parties should take precautionary measures to anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects. Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing such measures..” (UNCCC, 1992).

The key characteristic of precaution is the absence of certainty about the nature, likelihood or extent of the potential harmful effect of a substance or an activity. Thus, precaution is defined as “provident care”. The use of the precautionary approach takes into account that lack of full scientific certainty shall not be used as a reason for postponing decisions where there is a risk of serious or irreversible harm.  In scientific-based risk management and decision making, precaution is characterized mainly by the need for a decision, a risk of serious or irreversible harm and a lack of full scientific certainty. Governments are rarely able to act with full scientific certainty and cannot guarantee zero risk. Most new or emerging risks carry significant scientific uncertainty. Nonetheless, the need for decision making in the face of scientific uncertainty has increased with a corresponding increase in the emphasis on using precaution in decision making. 

Usually, the higher the perceived risk of a hazard, the more the lay public wants to see corresponding reduction of risk and implementation of regulation. However, expert perception tends to be more closely linked to expected annual mortality. The discrepancy between expert and public risk perception can result in conflict. The use of precaution in decision making can be especially useful in situations that involve a high amount of dread and uncertainty.  In the 1987 Science publication Perception of Risk by Paul Slovic, high “dread risk” is defined as perceived lack of control, dread, catastrophic potential, fatal consequences, and the inequitable distribution of risks and benefits. For example, nuclear weapons and nuclear power score highest for “dread risk” out of 81 hazards investigated across groups of lay people and experts judging large and diverse sets of hazards (Figure 1).


Figure 1. Location of 81 hazards on factors 1 and 2 derived from the relationships among 18 risk characteristics.  Each factor is made up of a combination of characteristics, as indicated by the lower diagram (Slovic, 1987). 


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