Re: st: Latent Growth Curve SEM GUI

[William Buchanan <william@williambuchanan.net>]

Hi Carter,

Can you copy the Mplus example into the e-mail?  I know several people will still have copies of Mplus, EQS, LISREL, and/or AMOS laying around and seeing what exactly you are trying to replicate would be helpful.  If you're using one of the example datasets from Stata or a publicly available data set that would be helpful to know as well.  

- Billy


On Jun 15, 2012, at 3:46 PM, Carter Rees wrote:

> Hi Billy,
> 
> The Mplus example comes from a stats workshop I attended. The model specification is the same as found in the Stata SEM manual (just a different variable measured at the 4 time points).
> 
> The Stata manual example of a latent growth curve also specifies the model without any covariates. So, I don't see any syntax that shows me how to do this. 
> 
> Carter 
> 
> On Friday, June 15, 2012 at 5:41 PM , William Buchanan wrote:
> 
>> Hi Carter,
>> 
>> Which Mplus example are you trying to replicate? It might just be that what you are trying to do would be better expressed via syntax than in the GUI. Have you looked through the [SEM] manual for Stata? There is a Growth Curve model in the examples section there which could probably give you a good idea of ways to modify the syntax to reproduce things correctly.
>> 
>> 
>> Billy
>> 
>> 
>> 
>> On Jun 15, 2012, at 3:19 PM, Carter Rees wrote:
>> 
>>> Using Stata 12 on a Mac. 
>>> 
>>> I have the basic latent growth curve model with 4 time points set up using the SEM GUI. I would like to add one time invariant covariate (gender) to predict the growth factors (intercept and slope) using the GUI. However, each time I try to add this variable either as latent or observed I get the error message "Cannot add path. Target variable will become endogenous and is correlated with exogenous variables". How do I add this via the GUI?
>>> 
>>> My goal is to replicate the results of an example from MPlus so I can get a better feel for what the Stata code will look like and how the GUI works. No troubles fitting the LGC without the covariate but the covariate is stumping me.
>>> 
>>> Thanks.
>>> 
>>> Carter
>>> 
>>> /*LGC without covariate*/
>>> sem (posT1 <- intercept@1 slope@0 _cons@0) ///
>>> (posT2 <- intercept@1 slope@1 _cons@0) ///
>>> (posT3 <- intercept@1 slope@2 _cons@0) ///
>>> (posT4 <- intercept@1 slope@3 _cons@0), ///
>>> latent(intercept slope) ///
>>> var(e.posT1@var e.posT2@var e.posT3@var e.posT4@var) ///
>>> means(intercept slope)
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> *
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>>> * http://www.ats.ucla.edu/stat/stata/
>> 
>> 
>> 
>> 
>> *
>> * For searches and help try:
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>> * http://www.ats.ucla.edu/stat/stata/
> 
> 
> 
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
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> *   http://www.ats.ucla.edu/stat/stata/


*
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