st: ssmenu, stcox and sample size estimates

[Simon <scmoore.lists@googlemail.com>]

<>

I have successfully installed Royston & Babiker's ssmenu (SJ2-2 st0013. 
 A menu-driven facility for complex sample size) and following the help 
file ran -ssmenu on- to which I received "Study size menu on.  The 
menubar has been changed." However, I cannot see any change in the menu 
bar. Is this compatible with Stata 11MP? If not, could someone suggest 
an alternative?

I have data from a pilot RCT, the unit of allocation is premises and 
each premises is subject to multiple failures. Data is described at the 
daily level with half of the premises (n=16) receiving the intervention 
half way through, the other half not. So I have run:

stset date, fail(fail) exit(time .) id(premises) enter(date0)
xi: stcox intervention,  efron robust schoenfeld(sch*) scaledsch(sca*) 
cluster(loc)

And from this I would like to estimate the number of premises required 
in the full study.

Wishing you well
Simon
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