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 design	No (%) of articles
	Substantive criticism in rapid responses (n=105)	Other articles (n=245)
Randomised trial	32 (31)	59 (24)
Cohort study	24 (23)	50 (20)
Systematic review	15 (14)	41 (17)
Cross sectional study	9 (9)	37 (15)
Case-control study	8 (8)	4 (2)
Mixed design or other	17 (16)	54 (22)

P=0.02 for test of similar distributions.