The Use of Screening in Policy Analysis

In most policy analysis studies there are a large number of alternative policies and a large number of impacts to be considered. Time and budget constraints make it impossible to calculate all the impacts for all of the alternatives. As a result, such studies include some process for reducing the number of alternatives to be examined in detail. The process is often implicit and nonscientific (e.g., only the decisionmaker's three favorite alternatives are considered). This paper suggests that policy analysis studies explicitly include a screening step, in which the alternatives to be examined in detail and those to be excluded from further consideration are chosen in a scientific and systematic manner. The output from this step is a relatively small set of policy alternatives that are sufficiently attractive that they deserve a more thorough evaluation. Two general screening strategies are described. They are illustrated by describing the screening step in a study to help determine an overall water management policy for the Netherlands.