for publication bias, and these methods can be used in the study of public participation.
We have already noted that the term “public participation” connotes a highly diverse set of activities. As discussed in Chapter 1, processes can be seen as more or less participatory along several dimensions, notably breadth (who is involved), timing (how early and at how many points in the overall decision-making process they are involved), intensity (e.g., the amount of time and effort participants spend and the degree of effort made by conveners to keep them involved), and influence. Although processes can be considered more participatory to the extent that they score more highly on these dimensions, the available research does not always make explicit distinctions among the dimensions. In reviewing the evidence, we comment on the effects of particular dimensions of participation when the evidence allows. We return in Chapter 5 to the issue of whether increases in participation along particular dimensions are associated with better outcomes. As we detail in Chapter 2, public participation processes also vary in their objectives (e.g., to make assessments or inform decisions, to reach consensus, or only to identify options and issues) and in the kinds of decisions they address. In Chapter 7, we examine how these differences may affect results.
This section shows that, on average, public participation is associated with better results, in terms of criteria of quality, legitimacy, and capacity. However, participatory processes can sometimes lead to undesired results that may be worse than what would have resulted from less participatory processes. The considerable variation in results is due largely to variation in the processes used to conduct public participation activities and in the extent to which these processes address the challenges posed by specific aspects of the context of participation. This evidence comes from a convergence of results from several sources.
An important source of evidence comes from experimental and quasi-experimental studies. Only a few experimental studies of participation processes have been conducted using control groups and random assignment to provide internal validity. Even fewer of these address environmental decision processes. Moreover, their practical value is unclear because it is hard to get an adequate sample of processes for statistical comparison, even if only one variable is manipulated. Quasi-experimental studies are a more common source of evidence on environmental decisions. These