Table 2

The type and number of component items contained in critical appraisal tools per study design.

Type of items

Design-specific critical appraisal tool components

Generic critical appraisal tool components

Total

Systematic reviews

Experimental studies

Diagnostic studies

Observational studies

Qualitative studies

Exp & Obs^a studies

All study designs

Study aims and justification

35

27

5

18

17

4

11

117

Methodology used

38

1

0

0

0

0

1

40

Sample selection

30

62

12

37

10

10

14

175

Randomization

2

65

1

5

0

6

5

84

Attrition

4

59

3

23

0

8

8

105

Blinding

1

77

5

8

0

5

7

103

Outcome measure characteristics

41

46

3

33

2

9

19

153

Intervention

7

42

3

13

0

5

12

82

Data analyses

83

91

14

54

12

14

27

295

Bias

24

14

2

5

0

3

6

54

External validity

72

50

12

30

27

9

27

227

Miscellaneous

11

12

7

5

7

2

6

50

Total

348

546

67

331

75

75

143

1485

Katrak et al. BMC Medical Research Methodology 2004 4:22   doi:10.1186/1471-2288-4-22