Bookmark and Share

Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.


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

Re: st: Setting a reference value by rows for calculating differences


From   Maarten Buis <[email protected]>
To   [email protected]
Subject   Re: st: Setting a reference value by rows for calculating differences
Date   Fri, 17 Jun 2011 08:57:13 +0200

On Fri, Jun 17, 2011 at 8:45 AM, CHERYL BARNABE <[email protected]> wrote:
> Hi there, trying to calculate the elapsed time from the baseline (or 1st visit) for each subject to subsequent follow-up visits, not the prior visit, but can't figure out the command to keep the first entry per subject as the reference
<snip>
> by study_id: generate visitmonth=(visitdate-visitdate[_n==1])

that should be:
by study_id: generate visitmonth=(visitdate-visitdate[1])

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/


© Copyright 1996–2018 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   Site index