NICE's use of cost effectiveness as an exemplar of a deliberative process.

This paper seeks to test 12 conjectures about the predicted use of deliberative processes by applying them to the technology assessment procedures used by the National Institute for Health and Clinical Excellence (NICE) in England and Wales. A deliberative process is one that elicits and combines evidence of different kinds and from different sources in order to develop guidance - in the present case, guidance for a health care system. A deliberative process entails the integration of three kinds of evidence: scientific context-free evidence about the general clinical potential of a technology, scientific context-sensitive evidence about particular evidence in realistic scenarios, and colloquial evidence to fit context-free scientific evidence into a context and to supply the best evidence short of scientific evidence to fill in any relevant gaps. It is shown that NICE's appraisals procedures and, in particular, its approach to cost effectiveness, entail both the weighing of each of these types of evidence and can be seen as rational responses to the 12 conjectures.