Table 1

Reasons for exclusion and number of excluded trials during the selection process of the first dataset

Reasons for exclusion

n


Lack of placebo-controlled, double-blind, randomized trial

Review, article, or comment

272

No placebo used

186

Lack of double-blinding or randomization

96

Kind of investigated symptom or condition

No clinical condition

44

Psychological, neurological or psychiatric condition

106

Subjective symptom

67

No classic placebo control group

Placebo as a dummy to maintain blinding of experimental treatments

147

Placebo as a control of an add-on treatment

74

Lack of stable disease condition

Medical intervention preceding experimental treatment

120

Co-medication changed during study

33

Acute condition

79

Developmental disorder

20

Trial focus on relapse or prevention

131

Trial focus on death or other serious events

113

Trial focus on long-term development of disease

121

Miscellaneous

Crossover design and results not separated by sequence

23

Native physiological parameter not reported

17

Insufficient detail to estimate placebo effect

40

Total

1689


Meissner et al. BMC Medicine 2007 5:3   doi:10.1186/1741-7015-5-3

Open Data