This Week In The Bmj
Cluster trials are vulnerable to biasBMJ 2003; 327 doi: https://doi.org/10.1136/bmj.327.7418.0-c (Published 02 October 2003) Cite this as: BMJ 2003;327:0-c
Log in using your username and password
Log in through your institution
Register for a free trial to thebmj.com to receive unlimited access to all content on thebmj.com for 14 days.
Sign up for a free trial