Table 1

Standardised GoR

Standardised GoRStrength of recommendation in guidelineLevel of evidence
AStrong recommendation against a test, medical intervention or healthcare service based on strong solid evidenceStrong evidence (eg, systematic reviews of RCTs or level 1 diagnostic studies, individual RCTs)
BRecommendation against a test, medical intervention or healthcare service based on moderate evidenceModerate evidence (eg, systematic reviews of cohort studies or level >2 diagnostic studies, individual cohort studies, ecological studies)
CRecommendation against a test, medical intervention or healthcare service based on expert consensusNo evidence possible or sought
DNo recommendation for or against a test, medical intervention or healthcare service because of unclear or conflicting evidenceWeak evidence (eg, systematic reviews of case–control studies or level 3b diagnostic studies, individual case–control studies, case series, poor or non-independent reference standard, expert opinion)
  • GoR, grade of recommendation; RCT, randomised controlled trial.