  | 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
st: rcal, measurement error model question
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
[email protected]
*
*   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/