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st: Modeling Paired Longitudinal - Covariance question
From
Jennifer A Hoff <[email protected]>
To
[email protected]
Subject
st: Modeling Paired Longitudinal - Covariance question
Date
Tue, 21 Dec 2010 09:05:25 -0500
The dataset I am working with is panel data �ongitudinal with
measurements in 2007,2008 and 2009.
I ran the model
xtset idnum year
xtgee outcome $demog $comobid_$covariates Med_group $yearlist
$MedgroupYear, family(gamma)link(power -0.5) robust i(idnum )
Next ran the data through a propensity score matching (one to one match)
on Med_Group. A variable called pair identifies which observations were
matched. Each member of the duo is assigned the same value for the
variable pair.
I want to re-run the above model on the propensity matched subset of the
original data . I realize the covariance structure needs adjusting for
the matched propensity pair. I have correlations between the repeated
measures of an individual - (accounted for with the xtset statement). But
I also have a correlation between the patient in Med_Group A that was
propensity matched/paired to a patient in Med_Group B. How do I adjust
the model to accommodate that?
---------------------------------------------------------------------------------------------------------
Jennifer Hoff Lindquist
Statistician
Health Services Research and Development
Mailing Address:
VA Medical Center
508 Fulton Street (152)
Durham, NC 27705
(919) 286-0411 Ext. 4054 (New as of 5/18/09)
[email protected]
[email protected]
---------------------------------------------------------------------------------------------------------
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