A clinical guideline is a set of instructions that are relevant at the bedside, and assist in decision making. These are not to be confused with protocols that simply state mandatory policies. Usually such protocols are not in a format suitable to assist clinical decision making in acute situations. Evidence-based guidelines are produced by national committees, colleges or expert bodies. These often take the format of a discussion document; they present the rationale behind a recommendation and often include a summary of the available evidence base. They are useful for background reading and in guideline preparation, but not for quick reference at the point of care. The National Institute for Health and Clinical Excellence (NICE) produces lengthy assessments and summaries that run to several pages. Again, these are helpful in guideline preparation but are far too cumbersome for bedside reference. Position statements are produced by the Royal Colleges, and are useful where they make clear recommendations, but often the clinician is given a choice of two or more options. This is appropriate in terms of framing research questions and defining an acceptable range of practice, but does not lead to standardisation of practice in a department.

The primary role of a clinical guideline is to improve patient care. Therefore, the ideal measure of a good guideline is improvement in clinical outcome. Organising a study to demonstrate such benefit even for one guideline is likely to prove challenging as a large randomised controlled study would be required, and in many instances this may not be practically possible to organise or fund. Consequently, the value of a guideline may be have to be assessed in other ways. This has been done in general practice in The Netherlands,¹ where it was concluded that a good guideline is one that …