Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Two baselines in stpiece


From   "Marika Jalovaara" <marika.jalovaara@helsinki.fi>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Two baselines in stpiece
Date   Wed, 05 Oct 2011 16:31:16 +0300

Quoting "Maarten Buis" <maartenlbuis@gmail.com>:

On Wed, Oct 5, 2011 at 11:34 AM, Marika Jalovaara wrote:
I'm using stpiece (or streg) to fit piecewise constant models. I'm wondering
whether it is possible to have separate baseline risks for two groups of
observations (say, dummy Group).

Fitting separate models for the two groups doesn't work because I should
perform tests of statistical significance for interactions between Group and
other covariates.

-stpiece- is user written. The Statalist FAQ asks you to specify where
you got user written software from. The reason for that is that there
are often multiple versions of the same user written program floating
around cyber space, and we obviously cannot answer questions about
unknown pieces of software. Typically, we will guess which version you
are using, but often that just leads to more confusion when we guess
wrong. So for all involved it is better to just read the FAQ and
follow the advise given in it, a link can be found at the bottom of
every post on statalist (including this one). Below I will assume you
have downloaded -stpiece- from SSC by typing in Stata -ssc install
stpiece-.

With the -tv()- option you can enter interaction terms between the
baseline hazard and some variable. This is typically interpreted as
allowing the effect of that variable to change over time, but since
interaction terms are symetric you can also interpret this as allowing
the baseline hazard to be different for different values of that
variable.

Hope this helps,
Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------
*
*   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/




The -tv()- option did it. Thank you!
Marika



--
Marika Jalovaara
post-doctoral researcher
Department of Social Studies, University of Helsinki
http://blogs.helsinki.fi/jalovaar/


*
*   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/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index