This paper reports upon the use of 'evidence' in the New Drug decision making practices of Trust hospital Drug and Therapeutic Committees. Based upon an ethnographic study of the decision practices of three DTCs over a nine month period, the paper analyses the management decision making of over thirty new drug requests and the types of evidence invoked in support or adoption of drug in therapy.

Employing ethnomethodologically based ethnographic research techniques focussing on the types of evidence invoked in locally situated activities of DTCs. The specific methods adopted included: non- participant observation, tape recording decision-making activities, collecting the documentary materials used in decision-making and depth-interviewing. The data collected included not only what evidence was involved in decisions were made by the DTC, but also the formulation of decisions once agreement was reached.

The results show that apart from clinical trial data, of which RCT data was the 'Gold Standard', other evidence invoked in the decision- making included: cost data; current prescribing; pharmaceutical company activities; decisions of other DCTs; patient demand; comparisons to other treatments; personality of the applicant and clinician's excitement. Further, these factors were not autonomous but were understood as inter-related to each other an local context by DTC members. The results also show how decisions to reject, accept or defer applications for new drugs involved partial accounts of the evidence discussed and the use of control and monitoring measures, again taking into account local issues.

In the discussion it is suggested that the 'real' rather than 'reported' activities of New Drug decision-making are key to the provision of adequate drug information. Further, it is argued that it is only through a reflexive understanding of decision making practices and the role of 'evidence' within these that this can be achieved. Rather than evidence being narrowly defined as text based scientific 'facts', this paper suggests that there are a number of other types of evidence, or factors, which may be constitute valid evidence in the local DTC decision making process. The evidence used, including 'scientific data' itself, must be understood as being embedded in the local needs and practices of the decision makers.

Finally, it is suggested that through the investigation of 'actual' on-going activities, at the level of inter-personal interaction, that 'evidenced-based' medicine (EBM) can be seen as 'real-world' activity. That practical localised issues are key to comprehending the 'realities' of implementing EBM. That knowledge of the various forms of 'evidence' employed and deployed in actual decision-making, can inform the content and design of information provision to assist 'real world' decision making on new drugs by pharmacists and other health service professionals engaged in managing new drugs.