Table 2-A: Quality of Evidence of Studies on the Effectiveness of Bispectral Index Monitors in Reducing the Incidence of Intraoperative Awareness.

Study Design	Level of Evidence	No. Eligible Studies
Large RCT,* systematic reviews of RCTs	1	1
Large RCT unpublished, but reported to an international scientific meeting	1(g)†
Small RCT	2	4
Small RCT unpublished, but reported to an international scientific meeting	2(g)
Non-RCT with contemporaneous controls	3a
Non-RCT with historical controls	3b	1
Non–RCT unpublished but reported to an international scientific meeting	3g
Surveillance (database or register)	4a
Case series (multisite)	4b	8
Case series (single site)	4c
Case series unpublished but reported to an international scientific meeting	4(g)
Total		14

^*RCT indicates randomized controlled trial.

^†indicates “grey literature” (preliminary reports of studies reported to international scientific meetings).