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 on April 23, and its replacement, statalist.org is already up and running.


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

Re: st: Correlation between 2 variables overtime- accounting for repeated measures


From   "JVerkuilen (Gmail)" <jvverkuilen@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Correlation between 2 variables overtime- accounting for repeated measures
Date   Sat, 16 Mar 2013 19:46:28 -0400

On Sat, Mar 16, 2013 at 6:49 PM, megan rossi <megan_rossi@msn.com> wrote:
> Yes The surgery was 1-3weeks after the baselines were taken...a fairly strict protocol. Then one year follow up and two year follow up...variable a &b were both low at baseline (still detectable and possibly correlated) but rise following surgery so are high at year 1 and year 2...perhaps best to just combine year 1 and 2 as if they're both high a correlation would be easier to find then if they're both low?
>

I don't think I'd combine them. You have different measures and that
should be respected.

To me the fact that this is longitudinal means that there's a clear
logical priority. I'd consider the first measurement as "causal" of
the second one, at least in some respect. So I'm not sure a pure
correlation makes sense. But I'd like to hear what others might say.

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


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