(Jasanoff 1987). Rigorously adhering to the science and the established rules regarding the inclusion of peer-reviewed or non-peer-reviewed material helps to ensure credibility. These preestablished norms are undoubtedly one reason the committee finds that many process assessments have been conducted successfully. Over the years, the knowledge and practice of conducting this type of assessment have been developed and refined by a core of experienced scientists and assessors, and have been successfully applied to multiple generations of stratospheric ozone assessments (WMO 1986a, 1990a,b, 1992, 1995, 1999, 2003, 2007) and the Intergovernmental Panel on Climate Change (IPCC) Working Group I (WG I) assessments (IPCC 1990a, 1995a, 2001a).
A well-established and successful model for process assessments has emerged that involves the following key elements:
Getting a critical mass of the world’s most respected scientists in the relevant fields to participate;
Ensuring broad participation and sponsorship;
Having an intensive, science-focused process of deliberation that is of such high quality that it attracts the number and quality of participation required and produces reports that can serve as authoritative scientific references in the field;
Urging the process to provide clear consensus evaluations of the state of knowledge on key policy-relevant questions, to the extent the underlying knowledge base allows;
Writing clear, compact summaries with the involvement and consent of the scientific author teams; and
Disseminating the summary messages prominently and consistently.
Even in the case of process assessments, it might be difficult to achieve the perception of legitimacy and credibility. Indeed scientists and other experts who participate in an assessment may have a different perspective on its legitimacy than others who expect that the outcome will affect their interests but are not intimately involved in the process (Jasanoff 1987). In practice, process assessments will be perceived as legitimate only if the intended target audience has ways of ensuring that the relevant questions are addressed and that scientific controversies of concern have been resolved to its satisfaction and by a process it considers legitimate (Jasanoff 1987). In the case of climate change in particular, many political actors realize that the conclusions drawn by process assessments, such as IPCC WG I, shift the momentum of policy decisions that are highly consequential for their actions. In turn, some actors external to the scientific community are increasing skeptical of these process assessments (McCright 2000; McCright and Dunlap 2003). If the sole purpose of the process assessment is to reach