SIGN guidelines are developed using an explicit methodology based on three core principles:
These principles have remained constant since SIGN was first established.
Although these core principles remain unchanged, detail of how they are reflected in practice has developed over the years. The latest major development has been implementation of the GRADE process. You can see a statement of how SIGN implements the principles of the GRADE process.
As part of the changes related to GRADE, SIGN decided as of 2013 not to continue with the ABCD grading of recommendations that had been in use since 2001. Reasons for this decision are set out in a separate policy document.
SIGN guidelines are based on a systematic review of the evidence, undertaken by guideline development group members, with support from the SIGN Executive. A detailed description of SIGN’s methodology is given in our handbook. This was originally our 50th guideline – and is therefore commonly referred to as SIGN50. The handbook is updated regularly to take account of any changes in methodology.
Downloadable versions of the documentation used by SIGN are available separately.
Useful tools for critical appraisal