Table 1

Standardised GoR

Standardised GoR	Strength of recommendation in guideline	Level of evidence
A	Strong recommendation against a test, medical intervention or healthcare service based on strong solid evidence	Strong evidence (eg, systematic reviews of RCTs or level 1 diagnostic studies, individual RCTs)
B	Recommendation against a test, medical intervention or healthcare service based on moderate evidence	Moderate evidence (eg, systematic reviews of cohort studies or level >2 diagnostic studies, individual cohort studies, ecological studies)
C	Recommendation against a test, medical intervention or healthcare service based on expert consensus	No evidence possible or sought
D	No recommendation for or against a test, medical intervention or healthcare service because of unclear or conflicting evidence	Weak 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)