Generate Starting Values for Group-based trajectory modelling in Stata?

I use your stata command traj to find the group-based trajectories. Usually, the comparison of BIC values from 1 to x groups leads to the decision to select the model with optimal groups.This command gives the optimal number of groups. I have read the help file for many times but i cannot find the way to get BIC values for different numbers of groups.

Does anyone use stata command traj to conduct group-based trajectory modeling? And how can i get the BIC values from models with different number of groups?

I have check the SAS codes. They include an option that I can set the number of groups. However, I have not installed SAS software in my computer. 

Thank you!

Yimin

I am using "traj" module in Stata. What would be the right way to store the data for further use. I mean, in SAS it is something like this:

PROC TRAJ DATA=A OUT=OF OUTPLOT=OP OUTSTAT=OS

But what would be the analogue in Stata? I get an error when trying:

traj, out(of) outplot(op) outstat(os) var(measure*) indep(age*) model(cnorm) min(0) max(10) order(2 1)

The error is either "variable op not found" or "option outstat() not allowed"

Any suggestions and references are appreciated. 

I am trying to study group-based trajectory modelling (GBTM). Please, notice that I am not a statistician. I have installed in Stata the module “traj” that is the same module as one for SAS. There are 13 different models one can use with traj.   

I have tried to find out on Internet the differences between them. I did understand something, but the most of it is still very unclear. Maybe somebody could explain it in an understandable way. My data: N=1500, 6 repeated measures (3 before the procedure and 3 after that), there is no need to specify the actual distance between these measures, the independent variable is continuous with min=0 and without max, there are a lot of zeros but not very many missing values. What would be the best choice of model?

Some references may also help. I have already read the articles by Nagin and Jones.

I am using panel data to search for the causality between two variables, and I think a Cross-lagged Panel Model would be appropriate. I have 8 waves and I want to run de model wave by wave in Stata. Could anyone please tell me how to do it?

Also, would a Dynamic Panel Analysis be more adecuate?

Thank you very much.

Usually, i use "lcmm" package in R - in order to perform growth mixture modeling (GMM).

However, i want to create a classification or groups based on two variables rather than one. I've read that this kind of modeling called "parallel growth mixture modeling". Is anyone knows how to perform such an analysis using R script?

I'm looking for suggestions/sample code to run SAS PROC TRAJ using a stratification variable that allows me to compare latent trajectories and covariate/risk effects across groups? I know this can be done using other software, but has anyone done this with PROC TRAJ? Many thanks in advance!

I am running a multinomial logistic regression. How do I change the reference category of independent variables that are categorical? I am familiar with changing the reference category of the dependent variable. But how does it work with independent variables? By default, the last category is taken as the reference group.

Dear RG Members,

I am testing the factor structure of some psychological scales. The participants have some missing values in their items answers.

Is it possible to use the multiple imputation procedures of Stata in combination with exploratory (EFA) and confirmatory factor analyses (CFA with SEM)?

Thank you.

Andrés.

I used the LatentGold6.0 to do LCA and the analysis results is under the question.

I'm curious about if the 5-Cluster's BIC or AIC not the lowest (the lowest BIC appointed to the 3-Cluster in pic1&pic2 /the lowest AIC appointed to the 6-Cluster in pic1&pic2 ), can't I select the 5-cluster? Thanks.