Levels of evidence and grades of recommendation

Sources of evidence in PROSPECT

The evidence for prospect is derived from three separate sources, and this evidence is taken into consideration by the prospect Working Group to determine the prospect recommendations:

??Procedure-specific evidence derived from the systematic reviews of the literature

??Transferable evidence from comparable procedures, or from other relevant sources, identified by the members of the prospect Working Group

??Current practice – a commentary on the interventions from the members of the prospect Working Group

??Practical prospect recommendations are based on all the information Study quality assessment All cited studies are assessed for quality of reporting of methodology and results (assessment performed by a medical writing team and the prospect Subgroup): 1. Statistical analyses and patient follow-up assessment: indicates whether statistical analyses were reported, and whether patient follow-up was greater or lesser than 80%. 2. Allocation concealment assessment: indicates whether there was adequate prevention of foreknowledge of treatment assignment by those involved in recruitment (A adequate, B unclear, C inadequate, D not used). 3. Numerical scores (total 1–5) for study quality: assigned using the method proposed by Jadad et al 1996, to indicate whether a study reports appropriate randomisation, double-blinding and statements of possible withdrawals. 4. Additional study quality assessment: including an assessment of how closely the study report meets the requirements of the CONSORT statement (additional assessment performed by the prospect Subgroup) Grading of recommendations based on overall level of evidence The recommendations are graded according to the overall level of evidence, which is determined by the quality of studies cited, the consistency of evidence and the source of evidence (as indicated in Table 2 below).