Apart from the suggestions by Joseph Coveney, these links may help:
http://www.jhucct.com/CCT/present/SCTMay2004/SCT%20poster.pdf- with a link to
Stata code
the FAQ by Al Feiveson: http://www.stata.com/support/faqs/stat/power.html
There is also the artmenu ado (findit artmenu: SJ5-1 st0013_1. A menu-driven
facility for complex sample size calculation randomized controlled trials with
a survival or a binary update) which is supposed to provide non-inferiority
sample size, however I haven't quite figured out how- the program does not seem
accept two proportions of the same size..
The equivsize.ado by Philip Ryan is working very well- but should be limited in
situations when proportions are less than 0.2- I wonder if other Stata based
alternatives for calculating sample size exists for e.g. non-inferiority
studies with small proportions (0.2)?
Jannik Helweg-Larsen, MD
Epidemiafdeling M
Rigshospitalet
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
