Table 6 Glossary of terms

Certainty:

Quality of the evidence or confidence in the evidence.

Direct estimates:

Effect estimate determined from a head-to-head comparison (such as study of A versus B).

Indirect estimates:

Effect estimate determined from two or more head-to-head comparisons through a common (such as the relative effect of A versus B by comparing the effect of A versus C and B versus C).

Network (multiple-treatment comparisons or multiple-treatment meta-analysis) :

Effect estimate determined for a particular comparison from the combination of direct and indirect effect estimates.

Loop:

A loop of evidence exists when 2 or more direct comparisons contribute to an indirect estimate (e.g., A-B and A-C, contribute to indirect B-C) this loop is considered closed if direct evidence exists between B-C, and open when this direct evidence does not exists.

Indirectness:

Term used in direct evidence to describe the presence of systematic clinical or methodological differences between head-to-head studies that can act as effect modifiers. These can be in different patients characteristics, ways of administering the interventions, measuring outcomes, or ROB.

Intransitivity:

Term used in indirect evidence to describe the presence of systematic clinical or methodological differences between head-to-head studies that can act as effect modifiers. These can be in different patients characteristics, ways of administering the interventions, measuring outcomes, or ROB.

Heterogeneity (Inconsistency):

The presence of differences in effect estimates between head-to-head studies that assessed the same comparison.

Incoherence:

The presence of differences in effect estimates between direct and indirect evidence.