The evidence base for this guideline was synthesised in accordance with SIGN methodology. An initial systematic review of the literature was carried out using an explicit search strategy devised by the SIGN Information Officer in collaboration with members of the guideline development group.

Searches were mostly restricted to meta analyses, systematic reviews, and randomised controlled trials, but were extended to cover observational studies in areas where other types of study were weak or non-existent. Inclusion criteria were the management, diagnosis and treatment of injuries to the head or neck from accident site through to discharge or transfer from the accident and emergency department. Intensive care of head injured patients, or maxilofacial injuries were specifically excluded.

Initial searches were carried out on the Cochrane Library, Embase, Healthstar, and Medline from 1985 through to September 1997. The main searches were supplemented by material identified by individual members of the development group and the evidence base for the guideline was updated during the course of development.

All selected papers were evaluated using standard methodological checklists before conclusions were considered as evidence.