Taken as a whole, these four papers on BRA suggest how evidential reasoning remains a process in which new techniques of inference must be socially grounded to be effective (Power, 1995). In common with other social histories of technological change, the success of BRA, and of its advocates such as Peecher et al., will depend on building alliances and on the successful marketing of effectiveness. A pedagogical change programme to create a new type of BRA expert will need to find ways to appeal to conservative interests with rhetorics of ‘business as usual’