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Table 2 Judgments for the 20 most common explanations of other bias

From: The judgement of biases included in the category “other bias” in Cochrane systematic reviews of interventions: a systematic survey

Explanation

Total

High, N (%); na

Unclear, N (%); na

Low, N (%); na

Not possible to assess other bias

504

7 (1.4);7

494 (98);117

3 (0.6);3

Baseline characteristics similar between the groups

314

0 (0);0

24 (8);13

290 (92);61

Not described/unclear

233

0 (0);0

226 (97);54

7 (3);4

Baseline imbalance between groups of participants

167

91 (54);56

62 (37);41

14 (9);12

Funding: industry

162

83 (51);28

77 (48);25

2 (1);2

Potential confounding factors

120

63 (53);38

47 (39);34

10 (8);9

Not enough information on baseline characteristics of participants

88

8 (9);6

78 (89);39

2 (2);2

Funding: non-profit

86

0 (0);0

4 (5);4

82 (95);33

Funding: not reported

72

0 (0);0

68 (94);15

4 (6);4

Important parameters not reported

61

19 (31);14

41 (68);28

1 (1);1

Sample size: calculation of sample size not provided

42

24 (57);6

17 (41);7

1 (2);1

Potential randomisation problem

40

9 (23);9

28 (70);13

3 (7);3

Potential problem with inclusion criteria

40

16 (40);15

22 (55);12

2 (5);2

Deviations from the study protocol

37

16 (43)

13

18 (49)

15

3 (8)

3

No relevant subgroup analysis

36

10 (28);1

26 (72);1

0 (0);0

Funding: intervention supplied by industry

32

14 (44);7

12 (38);10

6 (18);3

Adequate

28

0 (0);0

0 (0);0

28 (100);1

No information on the validity of the outcome measure

27

3 (11);3

23 (85);5

1 (4);1

Sample size: performed calculation

24

1 (4);1

3 (12);3

20 (84);9

Sample size: small

23

8 (35);5

15 (65);5

0 (0);0

  1. an = Number of Cochrane reviews that included at least one RCT with this characteristic