A model for managing uncertainty

Many students of disaster have concluded that uncertainty and communication are key factors in the management of emergencies. During emergencies, uncertainty increases and formerly dominant consensual views of problems and solutions often break down; different parties tend to evaluate the same evidence differently and, at times, tend to perceive different sorts of evidence. Such divergent interpretations create antagonisms and mistrust, which persist after the acute phase of an emergency has ended and complicate the tasks of recovery (Quarantelli 1988; Otway and Wynne 1989).

Our study of Seveso and other disasters (De Marchi, Funtowicz, and Ravetz 1993) suggests that there are six basic types of uncertainty (table 4.2) and eight distinctive strategies for managing the communication of uncertainty (table 4.3). Together, these two sets of variables provide the basis for a model of uncertainty management that has broad applicability.

Table 4.2 Types of uncertainty

Table 4.3 Strategies for communication of uncertainty

Situational uncertainty involves a poor match between the decisions that must be taken and the information at hand. It is normally the most salient type of uncertainty because information is central to decision-making. It is also a very common type of uncertainty because complete highquality information about major hazards is usually lacking. Moreover, interagency collaboration in decision-making is usually required and knowledge about the capabilities of such agencies is often incomplete.

In an ideal world, legal/moral uncertainty would not be salient because decisions would always be made in the public interest with due consideration of social justice; decision makers would be held free of liability. But few public decisions about industrial hazards meet these exacting criteria, so decision makers cannot ignore the possibility that they will be subject to legal action or moral censure. Concern about legal/moral uncertainty often leads to indecisiveness and defensiveness about the release of information.

Societal uncertainty occurs when institutions and the publics that they are intended to serve are not well integrated. Decisions that are subject to high degrees of legal/moral uncertainty also tend to be affected by societal uncertainty. Such uncertainty is most marked where every action is scrutinized by lawyers who represent other stakeholders. But societal uncertainty can be manifested in other ways. For example, respect for government agencies may be low, or individualism may be carried to extremes, either among the public or among leaders in major institutions.

Institutional uncertainty is brought about when agencies withhold information for bureaucratic reasons. It is most likely to be high in circumstances where there are difficulties about informal communication, acquaintance, and trust among personnel of agencies with different traditions and missions. This ensures that the necessary channels of understanding and confidence are absent during a crisis. Institutional uncertainty can be high even in relatively consensual societies, if there happens to be a tradition of bureaucratic secrecy.

When the parameters of confidentiality are strained, proprietary uncertainty becomes salient. Thus, in the midst of an emergency there may be a debate about the rights of persons to know, to warn, or to conceal.

Scientific uncertainty is the last (but by no means the least important) type of uncertainty. It is mobilized at various phases of hazard including before, during, and after emergencies. For example, (scientific) risk assessments that are undertaken well in advance of a crisis may employ long-established techniques to evaluate industrial plants and equipment but may have to depend on less-seasoned methodologies to analyse the transport of environmental pollutants (Funtowicz and Ravetz 1990). When a hazard is in the acute (emergency) phase, the possibility of effective forecasting may be either good or poor, depending on the circumstances (which themselves cannot always be predicted). Thus, scientific uncertainty can vary from low to very high.

Two sets of strategies (table 4.3) are available for communication of uncertainty, one of which is an attribute of people or agencies that make decisions; the other refers to the way in which communication is accomplished. Some people may decide to suppress information about uncertainty entirely, even from themselves. This may translate into a refusal to admit that uncertainty exists or a failure to notice it. It is an extreme form of discounting. Ordinary discounting will recognize a possibility but (as with many events in the distant future) will assign such a low value to its salience that it can be neglected for policy purposes. Recognition of an uncertain contingency is a balanced appreciation. By contrast, amplification is an emphasis - perhaps even an overemphasis - of the significance of uncertainty.

Corresponding to the interpretations are the policies concerning communication of uncertainties. At one extreme lies secrecy, the extreme case of confidentiality; then comes publicity, with its own extreme form - sharing. There are many variations and nuances in any practical policy of communication. The utility of these classification schema can be illustrated with reference to the Seveso disaster, the Seveso Directive, and the Karin B incident.