Anonymous posted on Monday, July 08, 2002 - 11:42 am
Dear Linda & Bengt:
I am running Mplus software using LSAY data set. I intend to run a six year logitudinal model including weight variable. However, it seems to me that in LSAY each year has its own weight variable. That is for six time points, there are six weight variables for each year. According to Mplus manual, I can use a weight variable for the whole six year data. I am wondering if you know how to specify these weight variables in Mplus. If you happened to analyze LSAY data set before, would you please inform me which weight variable did you use for a longitudinal analysis? I am a doctoral student and writing up my dissertation by analyzing a latent growth model using LSAY. Your information will be highly appreciated. Thank you very much.
Anonymous posted on Tuesday, July 09, 2002 - 9:17 am
If you can rewrite your model as a univariate type=twolevel you can use time varying weights.
bmuthen posted on Tuesday, July 16, 2002 - 10:21 am
We have not used weights in our LSAY analyses. I assume that there is also a time-invariant weight variable.
Anonymous posted on Tuesday, February 15, 2005 - 4:18 pm
Dear Linda and Bengt I have an LGC model were i have time-varying binary indicators of a "treatment" at each time point. I have calculated an overall Propensity scores model, beforehand thus each individual has a PS score. Hirano et al (2003) use PS scores p(xi), as weights wi, where wi=p(xi)/[1-p(xi)]. What do we know about using the weights wi into an LGC model? Should i trust in the standard errors that MPLUS generates?
Or it is better to incorporate the paths from a PS observed variables predicting the time-varying variable for Treatment effects at each time point.
What are the differences between these two approaches?
If you use sampling weights in Mplus, the standard errors are trustworthy. I do not know what the results would be if you use propensity scores as sampling weights. There are several Web Notes on the Mplus website that discuss sampling weights in Mplus.
Because of this, I would use the propensity scores as variables in the model.
I'm trying to run some latent growth models using sampling weights. I have already successfully estimated these models without weights. Now, even when estimating the simplest unconditional growth model, I receive the message
no convergence. serious problems in interations. estimated covariance matrix non-invertible. check you starting values.
My syntax is:
USEVARIABLES ARE rc1rdirt rc2rscal rc4rdirt rc5rdirt rc1mirt rc2mscal rc4mirt rc5mirt; MISSING ARE blank; WEIGHT IS c1_5fp0;
I'm running a growth model on 3 time points for 3 groups of persons. I want to know if the trajectories of my 3 groups are the same. So I put 2 dicho variables in the model (tcseul and toseul) and I find that itís different. But, I know that in one of my groupe I have more female and I whant to be sure that the difference that I found was not because of the inequal proportion of female. How can I control this?
Thank you and there is my input
variable: names are id sexe age tdah groupe tc1 tc2 tc3 opp1 opp2 opp3 toseul tcseul tcxs oppxs;