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st: rcal, measurement error model question


From   Richard Valliant <rvalliant@survey.umd.edu>
To   statalist@hsphsun2.harvard.edu
Subject   st: rcal, measurement error model question
Date   Thu, 11 Dec 2008 11:07:46 -0500

I'm a new user who is trying to fit a simple measurement error model to
a set of estimates from two independent surveys.  The surveys are
measuring the same things.  My data look like
 
(e1, v1) = set of 30 estimates and their variances from survey 1
(e2, v2) = set of 30 estimates and their variances from survey 2

The model I want to fit is basic: 
e1 = a + b*e2 + u1
e2 = E2 + u2     (u1 and u2 are the model errors, E2 is E(e2)  )

I've tried:
  mkmat v2
  mat D = diag(v2)
  rcal (e1) (w: e2), suuinit(D)

This gives "invalid syntax". If I put some arbitrary variable x in the
model (which I don't want), this works:
    rcal (e1=x) (w: e2), suuinit(D)

But rcal apparently does not allow aweights to account for v1 =
var(e1). 
Is there a way to use rcal or some other procedure to fit the model
above, accounting for the fact that I have (1) estimates of variance for
both e1 and e2 and (2) no covariates measured without error to put in
the model?

Thanks in advance,
R. Valliant
U. of Maryland
rvalliant@survey.umd.edu

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