Re: Re: st: sts graph: different results with -atrisk- vs -risktable- option

[Charles Lindsey <clindsey@stata.com>]

Alex Gamma <alex.gamma@uzh.ch> separately used the -atrisk- and
-risktable- options in two -sts graph- calls with data that contained
multiple records per subject.  There was a large discrepancy in the
results from the two calls.  The graphed -atrisk- numbers were
significantly larger than the -risktable- numbers.  Alex compared with
-sts list- as well, and found these numbers matched the -risktable-
numbers.  Some of the -atrisk- numbers actually exceeded the total
number of subjects in Alex's dataset.

Joerg Luedicke <joerg.luedicke@gmail.com> investigated the issue with
-atrisk- and -risktable- that Alex discovered.  He also found that some
of the -atrisk- numbers exceeded the total number of subjects in the
data.

This is a bug in -sts graph, atrisk- that can arise in multiple record 
survival data.  We are investigating and will provide a solution in a
future ado update.

--Charles Lindsey
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/