JES wrote:
> I am a grad student taking a course in MRC and have a problem with a project
> I am working on. I think I may have bitten off more than I can handle with
> this one and would appreciate any insight you can give me.
> I have data from a longitudinal study in which a type of treatment was
> developed for chronic pain. In the analyses, I am looking at the baseline
> measures and the final time measures. The main variable of interest is the
> pain report at baseline and final.
> I am interested in determining if the change in any of the other variables
> contributed to the variance of the final pain measure. Specifically,
> ratings of depression, anxiety; as well as physiological variables such as
> heart rate, blood pressure, and respiration rate.
> My problem is that I am looking at change in one variable and trying to
> determine how it affects change in another variable. I would like to do an
> MR analyses, maybe using the residuals from baseline/time 2.
John:
Here is an example using one of your proposed predictors. If you
set up a regression model in which PAIN2 is predicted by PAIN1,
HRATE1, and HRATE2, then the coefficient for HRATE2 can be interpreted
as the effect of changes in HRATE on changes in PAIN. It would be
important to enter the variables into the equation in the order above
unless you were only interested in the HRATE2 coefficient. If you are
only interested in HRATE2 then all the variables could be entered on a
single block/step.
You should probably examine the stabilities of PAIN and all the
predictors. Also, correlations among residualized change scores may
be useful descriptively and could help you interpret the multiple
regression results.
You may find the following little green Sage book to be very useful:
Finkel, S. E. (1995). Causal analysis with panel data (Sage University
Paper series on Quantitative Applications in the Social Sciences,
07-105). Thousand Oaks, CA: Sage.
Hope this helps,
Chuck
----------------------------------------------
Chuck Cleland
Institute for the Study of Child Development
UMDNJ-Robert Wood Johnson Medical School
97 Paterson Street
New Brunswick, NJ 08903
phone: (732) 235-7699
fax: (732) 235-6189
http://www2.umdnj.edu/iscdweb/
----------------------------------------------
===========================================================================
This list is open to everyone. Occasionally, less thoughtful
people send inappropriate messages. Please DO NOT COMPLAIN TO
THE POSTMASTER about these messages because the postmaster has no
way of controlling them, and excessive complaints will result in
termination of the list.
For information about this list, including information about the
problem of inappropriate messages and information about how to
unsubscribe, please see the web page at
http://jse.stat.ncsu.edu/
===========================================================================
