Nonetheless, Bayesian methods are a controversial topic in that they may involve the explicit use of subjective judgements in what is conventionally supposed to be a rigorous scientific exercise. The BIDS ISI database was searched using the terms 'Bayes' or 'Bayesian'. This yielded almost 4000 papers published in the period 1990-98. There has been very limited use of proper Bayesian methods in practice, and relevant studies appear to be relatively easily identified. Results Bayesian methods in the health technology assessment context Different contexts may demand different statistical approaches.
Prior opinions are most valuable when the assessment forms part of a series of similar studies.
A decision-theoretic approach may be appropriate where the consequences of a study are reasonably predictable. The prior distribution is important and not unique, and so a range of options should be examined in a sensitivity analysis. Bayesian methods are best seen as a transformation from initial to final opinion, rather than providing a single 'correct' inference. The use of a prior is based on judgement, and hence a degree of subjectivity cannot be avoided. However, subjective priors tend to show predictable biasses, and archetypal priors may be useful for identifying a reasonable range of prior opinion.