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From | Samantha Molbach <samantha.molbach@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Implementation of Latent Variable Model with SEM Builder |
Date | Sat, 14 Apr 2012 07:55:49 +0200 |
Dear Statalisters, I need some help in implementing a Structural Equation Model in Stata 12. I want to create a health index according to Bound (1999): "The dynamic effects of health on the labor force transitions of older workers". I have the following variables available: Self-assessed health on a five-point scale (SAH), Age, Education, different objective measures of health such as blood pressure (Blood), chronic diseases (chronic) and physical limitations (limit). The theoretical model is the following: H = X*ß1 + Z*ß2 + u with H=true health; X= socioeconomic variables; Z=objective health measures; u=error term I do not observe the true health, but only the self-assessed health which includes a reporting error e, thus: SAH = H + e SAH = X*ß1 + Z*ß2 + v (with v=u+e) I estimate the last equation via SEM the following way: sem (age -> sah) (education -> sah) (blood -> sah) (chronic -> sah) (limit -> sah) Then, I'm stuck - how do I get back to the first equation and model the health indicator H? Also, can I estimate an ordered Probit model in SEM? I tried to use "SEM-Predictions", but I have the feeling that I need to define a latent variable first in the SEM model. I'm totally new with latent variable models - could it be that both the health index and SAH are latent variables with the latter one being endogenous? I hope that my problem is understandable. Any help will be very appreciated, also some literature advice - thank you very much in advance! Samantha * * 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/