and systems engineering (Howard et al . 1977). In the context of environmental 

 assessment, decision analysis assumes the additional dimension of iterative and 

 adaptive application to an evolving problem (pollution) as our basic understanding 

 of ecosystem function grows. This added dimension derives from the stability 

 and resiliency of ecosystems which allow us to research the validity of our 

 understanding and predictions after instituting the policy that resulted from 

 those same predictions. In this adaptive environmental assessment and management 

 approach (Holling 1978), however, the basic decision analysis remains the same. 

 Modeling needs that arise from the decision analysis itself, as opposed to 

 fundamental cause-effect relationships in the marine ecosystem, are outlined in 

 the next section. 



MODELING REQUIRED FOR DECISION ANALYSIS 

 OF POLLUTION MANAGEMENT PROBLEMS 



Decision analysis is merely a structured procedure for analyzing the merits 

 of various alternatives in a decision. Decision analysis helps to ensure that 

 essential steps have been consciously considered in the decisionmaking process 

 and also facilitates explicit documentation of the form and content of those 

 considerations. For decision problems as complex as marine pollution management, 

 in which tradeoffs must be balanced among economic costs, human health values, 

 commercial and sports fishery production, recreational and wilderness values, 

 and global human habitat values, over potentially large scales of- space and 

 time, it is important to document the analysis as completely as possible to 

 provide both a logical justification for the chosen policy or alternative and a 

 basis for improved decision making in the future. 



Careful, complete, and objective documentation of the decision process is 

 particularly important in matters of public policy, such as marine pollution, 

 where numerous different factions, with different perceptions of the problem 

 and different values on the potential outcomes, may be affected by the decision. 

 The documented analysis serves to inform all concerned on the specific consider- 

 ations that entered the decision and provides a basis for iterative objective 

 improvement in successive applications of the analysis. 



Matheson and Howard (1968) have succinctly outlined a comprehensive approach 

 for the analysis of decisions and the identification of optimal alternatives, 

 which is summarized in the following section. The sequence of steps involved 

 in the analysis (fig. 3) involves the creation and manipulation of a hierarchy 

 of models (fig. 4) through which the relative merits of each available alterna- 

 tive are assessed. These steps are consistent with the elements of a rational 

 decision process discussed earlier (fig. 1). 



The minis ti c phase of the decision analysis focuses on the development 



and sensitivity analysis of the structural and value models used in predicting 

 outcomes and values for each identified alternative. For assessment of marine 

 pollution decisions, the structural model would address the environmental 

 processes outlined in table 3 following the structure suggested on pages 13-14 

 and in figure 2 to generate a set of outcome variables (table 2) for each 

 alternative. The value model Is designed to assign each outcome a value, by 

 translating each member of the set of outcome variables (table 2), as defined 

 and quantified in time and space, into an appropriate measure of value. A time- 

 preference model is also created to translate values that occur over a timestream 



14 



