OpenSEM Forums
ethibodeau
Joined: 05/16/2018
LGM age definition variables, standard error in intercept mean/variance
In OpenMx, if I run a latent growth model with age definition variables and center my intercept at some age (by subtracting that number from each person's age), will the standard error of the intercept mean and variance depend on the number of people at or around that age? For example, if I have a longitudinal study that in the first wave a cross-section of people were recruited ages 10-40y and then followed every 5 years. Even if my total sample size was reasonable (1000) there are a lot less people at any given age, especially younger ages.
dcep
Joined: 12/11/2018
Postulating mixed effects model with random intercepts and slopes
Could you please help me translate the following model in the picture to OpenMx syntax using path specification?
Latent variables depict latent intercepts and latent slopes.
I am a beginner in OpenMx and need to check the model urgently.
I would be really grateful if you could help.
metinbulus
Joined: 11/17/2018
Measurement invariance in CFA with ordinal data (converegence issues)
Hi all,
I have been trying to replicate measurement invariance for the CFA model with ordinal data (theta parametrization) in Kline (2015) but have failed due to convergence issues (even after roughly adjusting starting values for thresholds based on lavaan output). I also tried mxAutoStart(). I am wondering if I am missing something.
library(OpenMx)
radloffdata <- read.table("https://www.guilford.com/add/kline/radloff-lavaan.txt", sep="\t", header = FALSE)
colnames(radloffdata) <- c("x1", "x2", "x3", "x4", "x5", "g")
chancey
Joined: 09/09/2017
Fit tests for ACE models
Good morning,
I am running an ACE model for an ordered categorical outcome using script adapted from [Maes](http://ibg.colorado.edu/cdrom2016/maes/UnivariateAnalysis/one/oneACEo.R). I seem to be able to generate most indicators of model fit, including AIC, BIC, -2LL and p-values associated with likelihood-ratio tests for nested models. However, I cannot seem to generate an associated chi-square value. Is there a simple way to generate chi-square value for these tests? Thanks,
Chance
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ZZ
Joined: 07/22/2018
Example Scripts for mxComputeEM?
Dear All,
I wonder if anybody could share example scripts involves using mxComputeEM?
The only sample code I found is in paper by Paritikin, Hunter, and Boker 2015 conducting item factor analysis https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4822086/, where mxComputeEM is called with arguments: "expectation = , predict = ". However, as the help file (version 2.11.5) of mxComputeEM suggests, these two arguments are deprecated, and an argument called "estep" should be used.
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MaximilianStefan
Joined: 12/04/2018
LGCM with Measurement Models and Latent Factor Predictor
Hi,
I am currently trying to fit the following model model: (picture, code and outcome attached)
I have data for 5 waves (2012-2016) on 4 observed Variables (-> x1_12, x2_12, ..., x4_16) that form a latent factor (= 5 CFAs for 5 years). (latent factor Naming: f12, f13, ..., f16)
The observed Variables have a range from 1-3, so I treated them as ordinal Variables.
I would like to fit a LGCM to those Factors.
Liz
Joined: 04/20/2016
Veronica_echo
Joined: 02/23/2018
Is there a way to add covariates in growth mixture model
Hi,
I have a script for the 2-class growth mixture model (please see attached). I am wondering if I can add covariate (say x1) as a covariate of my model. I may want to see the effect of x1 on the latent classes only and also of it on both latent classes and the growth factors. As my understanding, in MPlus, the first scenario can be expressed as "c#1 on x1" and the second one can be written as "c#1 on x1" and "int on x1; slp on x1" of each class, but I have zero idea to translate to OpenMx. Any advice would be appreciated.
cdmcdermott221
Joined: 10/09/2018
3-level longitudinal latent growth curve model
Hello all,
I posted this question in the Mixed Effects and Nested Models discussion board, but haven't heard back in a few weeks and my analysis is a bit time-dependent.
noamm
Joined: 10/10/2018