Table 2

Composition of Reference Standard

Study design
Total
MEDLINE
EMBASE

N
%
N
%
N
%

Comparative – prospective
19
(8.7)
18
(8.7)
16
(8.4)
Comparative – retrospective
16
(7.4)
14
(6.8)
13
(6.8)
Case series – prospective
104
(47.9)
99
(48.1)
93
(48.7)
Case series – retrospective
70
(32.3)
67
(32.5)
61
(31.9)
Case series – unclear
8
(3.7)
8
(3.9)
8
(4.2)

TOTAL
217
(100.0)
206
(100.0)
191
(100.0)

Fraser et al. BMC Medical Research Methodology 2006 6:41   doi:10.1186/1471-2288-6-41