Table 2

Distribution and baseline characteristics of sample abstracts


CCT
OCR
BSS
Total

Total
326
455
219
1,000
          analytical design
326(100%)
331(73%)
174(79%)
831 (83%)
          descriptive design
-
124 (27%)
45 (21%)
169(17%)
Country region




          US/Canada
88 (27%)
181 (40%)
121 (55%)
390 (39%)
          NW-Europe/Austr.
138(42%)
135 (30%)
44 (20%)
317(32%)
          SE-Europe
52(16%)
62 (14%)
9 (4%)
123 (13%)
          other
48(15%)
77(17%)
45 (21%)
170 (17%)
Language




          no or minor errors
301 (92%)
416(91%)
210(96%)
927 (93%)
          major errors
25 (8%)
39 (8%)
9 (4%)
73 (7%)
Median sample size/group




          subtype 1
parallel: 30
T & D: 22
animal: 6

          subtype 2
cross over: 10
epid.: 38
other: n/a

          subtype 3

physiol: 10


Quality score




          median
0.66
0.52
0.51

          IQR
0.62–0.70
0.44–0.58
0.44–0.57

Stat. significancea




          positive
140 (43%)
149 (45%)
65 (37%)
354 (42%)
          negative
99 (30%)
41 (12%)
7 (4%)
147(18%)
          equivocal
87 (27%)
141 (43%)
102 (59%)
330 (40%)

aanalytical studies only

Timmer et al. BMC Medical Research Methodology 2001 1:13   doi:10.1186/1471-2288-1-13