LPA with unequally spaced time points PreviousNext
Mplus Discussion > Latent Variable Mixture Modeling >
Message/Author
 Gregory posted on Tuesday, December 27, 2016 - 2:12 am
Hello, I have a question regarding how to specify a syntax for LPA with unequally spaced time points.

The model is aimed to identify different classes of trajectories that reflect the change in measurements over time. The time points are unequally spaced among subjects. Measurements are continuous variables. Data are wide.

I've seen the example (http://www.ats.ucla.edu/stat/mplus/faq/tscore.htm) of how to run a growth model with unequally spaced time points, but such approach does not accept 'tscores' for type = MIXTURE showing the following mistake: "TSCORES option is only available with TYPE = RANDOM."

Could you please help me with how to specify the syntax for my model?

TITLE:
Entering data from .csv file
DATA:
FILE IS "E:/file.csv";
VARIABLE:
NAMES ARE
id v1-v40, t1-t40;
USEVARIABLES ARE
v1-v40, t1-t40;
TSCORES = t1-t40;
MISSING ARE ALL(999);
CLASSES = CLASS(3);
ANALYSIS:
TYPE IS MIXTURE MISSING;

MODEL:
%OVERALL%
I S Q C | v1-v40 at t1-t40;
%CLASS#1%
Q@0;
C@0;
%CLASS#2%
Q@0;
C@0;
%CLASS#3%
Q@0;
C@0;
 Bengt O. Muthen posted on Tuesday, December 27, 2016 - 4:59 pm
Try Type = Mixture Random;
 Gregory posted on Wednesday, December 28, 2016 - 3:17 am
Bengt, thank you for the answer and making the experience of using Mplus pleasant. It works!
 Gregory posted on Monday, January 02, 2017 - 6:17 am
Dear Bengt,

In relation to this, I also have a question: how can I plot the values of the measurements over time, taking into account that the time points are irregular per subject?

Normally I would do that like this:
PLOT:
TYPE IS PLOT3;
SERIES IS v1-v40 (*);

adding "AT t1-40" shows the mistake:

"Unknown variable in SERIES option: AT"
 Linda K. Muthen posted on Monday, January 02, 2017 - 7:55 am
The AT option cannot be used with SERIES. This type of plot is not available.
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