Table 1

 Study design of research papers with substantive criticisms in rapid responses section of electronic BMJ compared with other research papers published in BMJ

Research designNo (%) of articles
Substantive criticism in rapid responses (n=105)Other articles (n=245)
Randomised trial32 (31)59 (24)
Cohort study24 (23)50 (20)
Systematic review15 (14)41 (17)
Cross sectional study9 (9)37 (15)
Case-control study8 (8)4 (2)
Mixed design or other17 (16)54 (22)

P=0.02 for test of similar distributions.