Mass mailing a printed bulletin which summarises systematic review evidence may improve evidence-based practice when there is a single clear message, if the change is relatively simple to accomplish, and there is a growing awareness by users of the evidence that a change in practice is required. If the intention is to develop awareness and knowledge of systematic review evidence, and the skills for implementing this evidence, a multifaceted intervention that addresses each of these aims may be required, though there is insufficient evidence to support this approach.
Reduction in the use of surgery for glue ear: did national guidelines have an impact?
It is widely accepted that the passive dissemination of national clinical guidance has little or no impact on practice.
                To assess the impact in England of an Effective Health Care bulletin on childhood surgery for glue ear issued in 1992 and to understand the reasons for any change (or lack of change) in practice that ensued.
                Time series analysis of the rate of use of surgery by children under 10 years of age from 1975 to 1997/8 in 13 English health districts.
                Following a rise in the rate of surgery in public (National Health Service) hospitals from 1975 to 1985, the rate declined by 1.6% a year from 1986 to 1992/3. Following publication of the guidelines in November 1992, the rate of decline increased to 10.1% a year. Even after allowing for a slight increase in the use of independent (private) hospitals between 1992/3 and 1997/8, the overall rate of decline was at least 7.9%. It appears that the rate of referral of cases by primary care physicians (general practitioners) halved during this period. Several contextual factors are thought to have contributed to the effect of the guidelines, including pre-existing professional concern about the value of surgery, the introduction of an internal market into the NHS, and growing apprehension among parents fuelled by scepticism in the mass media. During this unprecedented period of rapid change in usage, staff delivering the service remained unaware of the alterations in their own practice.
                Passive dissemination of national guidelines can accelerate an existing trend in clinical practice if the context is hospitable. Policy makers should identify and target such situations.