Skip to main content
. 2009 Nov 1;9(17):1–42.

Table 4: Quality of Evidence of Included Studies*(31).

Study Design Level of
Evidence
Number of
Eligible Studies
Large RCT, systematic review of RCTs 1      0
Large RCT unpublished but reported to an international scientific meeting 1(g)      1
Small RCT 2      7
Small RCT unpublished but reported to an international scientific meeting 2(g)      0
Non-RCT with contemporaneous controls 3a      0
Non-RCT with historical controls 3b      0
Non-RCT presented at international conference 3(g)      0
Surveillance (database or register) 4a      0
Case series (multisite) 4b      0
Case series (single site) 4c      0
Retrospective review, modeling 4d      0
Case series presented at international conference 4(g)      0
*

g refers to grey literature; RCT, randomized controlled trial.