Abstract

This chapter looks at how expert consensus processes specify who is an “expert” and what constitutes “consensus”. There are a number of attributes that have been used to specify who is a scientific expert, including professional qualifications and work experience, membership of scientific or professional organizations, peer-reviewed publications, specialist conference attendance and nomination by other experts. A common factor across these attributes is acknowledgement of expertise by peers. Where consensus has to be reached on matters of values as well as scientific questions, the values of all interested parties must be considered, which may include the general public, cultural experts or consumer advocates as well as scientists. When consensus occurs spontaneously, there is no formal process to ascertain agreement, but there are indicators that it has occurred, such as a high rate of positive citations and incorporation in textbooks. With deliberative consensus, the level of agreement among experts is quantified. However, what level of agreement is required for “consensus” depends on the purpose, with a higher level needed for establishing likely scientific truth than for defining concepts and standardizing measures.