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Mplus Discussion > Growth Modeling of Longitudinal Data >
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 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.

Sincerely,

Chih-chun
 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?
 Linda K. Muthen posted on Wednesday, February 16, 2005 - 7:24 am
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.
 Peggy Clements posted on Wednesday, September 20, 2006 - 1:29 pm
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;

ANALYSIS: TYPE = general;
ESTIMATOR = MLR;
MODEL:
read_i read_s | rc1rdirt@0 rc2rscal@1 rc4rdirt@3 rc5rdirt@7 ;
math_i math_s | rc1mirt@0 rc2mscal@1 rc4mirt@3 rc5mirt@7;

The tech5 output indicates that there are 13 iterations.

Thanks.
 Thuy Nguyen posted on Thursday, September 21, 2006 - 11:21 am
This type of question would be better handled through Mplus support. Please send input, output and data to support@statmodel.com.
 Phil Herzberg posted on Thursday, September 28, 2006 - 1:19 am
How is the command that all variables of the input file are saved and not only the USEVARIABLES. It is the id variable that should also be saved.

Thanks
Phil
 Phil Herzberg posted on Thursday, September 28, 2006 - 5:26 am
DATA:
FILE IS "C:\TEMP\m3.txt";

VARIABLE:
NAMES ARE y1 y2 y3 y4 y5 y6 y7;
USEVARIABLES ARE y2 y3 y4 y5 y6;
CLASSES = c(3);

ANALYSIS:
TYPE IS MIXTURE;
LOGHIGH = +15;
LOGLOW = -15;
UCELLSIZE = 0.01;
ESTIMATOR IS MLR;
LOGCRITERION = 0.0000001;
ITERATIONS = 5000;
CONVERGENCE = 0.000001;
MITERATIONS = 5000;
MCONVERGENCE = 0.000001;
MIXC = CONVERGENCE;
MCCONVERGENCE = 0.000001;
MIXU = CONVERGENCE;
MUCONVERGENCE = 0.000001;

MODEL: %OVERALL%

%c#1%
y2 y3 y4 y5 y6;

%c#2%
y2 y3 y4 y5 y6;

%c#3%
y2 y3 y4 y5 y6;


OUTPUT: SAMPSTAT RESIDUAL STANDARDIZED TECH1 TECH4 TECH7;

PLOT: Type is Plot1 Plot2 Plot3;


SAVEDATA:
FILE IS results_3;
FORMAT IS FREE;
RECORDLENGTH = 1000;
SAVE = CPROB;

OUTPUT:

SAVEDATA INFORMATION

Order of variables

Y2
Y3
Y4
Y5
Y6
CPROB1
CPROB2
CPROB3
C

Save file
results_3

Save file format Free

Save file record length 1000


I would like to store also the ID variable y1.

Thanks
 Bengt O. Muthen posted on Sunday, October 01, 2006 - 12:52 pm
You define y1 to be an IDVARIABLE (see UG).
 Annie Desrosiers posted on Thursday, February 08, 2007 - 12:32 pm
Hi!

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;

usevariables are tcseul toseul opp1-opp3;

missing = . ;

analysis: type = missing H1;

model: i s | opp1@0 opp2@1 opp3@1.325;
i s on tcseul;
i s on toseul;

output: sampstat;
 Linda K. Muthen posted on Friday, February 09, 2007 - 8:40 am
You can add gender as a covariate:

i s ON tcseul toseul gender;
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