OpenMx Structural Equation Modeling
Manuel Rein
Joined: 04/01/2024
Vivian
Joined: 04/30/2025
IvanVoronin
Joined: 08/18/2013
Mixed effects model - matrix specification
Hello,
I am looking for advice with regard to the implementation of mixed effects model in OpenMx.
I am starting with a simple model where one dependent variable Y is predicted by four correlated variables X1-X4. The participants in the sample are clustered in pairs (they are twins).
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Ilaria
Joined: 07/22/2024
Problems with Constrain expected Means and Variances to be equal across Twin Order
Hi all,
I am trying to fit several bivariate [between my exposure at age 16 and my outcomes at age 21 (accounting for age and sex)] and trivariate [my exposure at age 16 and my outcomes at ages 21 and 26 (also accounting for age and sex)] ACE models. However, I’ve started by fitting univariate saturated and submodels, followed by ACE and submodels, to eventually fit my bivariate models. The saturated models run fine across all, but when I try to fit the constrained models (by twin order and zygosity), I get the following error message:
didenursahin
Joined: 03/20/2023
outdated-solved
outdated-solved
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Tugce Yildiz
Joined: 01/15/2024
NA CIs for Bivariate Model
Hi, I am trying to run a bivariate model with two variables and 2 covariates. However, I get NA !!! for BivA, BivC and BivE. Can you help me solve this issue?
Here is the script:
### SELECT VARIABLES HERE
data_file <- "Cerebellum_volumes.csv"
variable_input1 <- "lsas_total"
variable_input2 <- "Vermis_VII"
cov1 <- "Total_Cerebel_Vol"
cov2 <- "age"
### Import data
dat <- read.csv(file=data_file, header=TRUE, sep = ";")
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lior abramson
Joined: 07/21/2017
checking total h2 at time 2 in a longitudinal choelsky model with paths script
Hello,
I am conducting a longitudinal Cholesky model with one variable in two time points.
I use the script written below with paths.
How can I modify this script to find for the total h2 at time 2? that is, I want to find the heritability explained by both the genetic effect from time 1 and the genetic effect from time 2, and the confidence interval of this estimate.
Thank you very much for your help
jkraemer
Joined: 12/18/2022
goodness-of-fit indices for ML SEM
I have been asked by a reviewer to offer a better justification for the fit of my proposed ML model by "indicating the fit of the within and between model separately". After reading several chapters made for MPlus, I first looked to mxRefModels(). But, I am under the impression that it does NOT work with ML SEM. So, I tied to make the saturated and independence models for within and between myself for the various calculations. I was successful regarding the independence model but not the saturated model.
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Ben
Joined: 06/20/2023
Best Practices for 3lvl measurement SEM
I'm currently building a 3lvl MSEM including measurement models. The Pritikin et al. (2017) paper is relevant and helpful but whereas they have observed variables on every level, I mainly want to use levels to control for the between-part of the variance of items I measured only on the 1st level. Hence, I want to make sure I don't misclassify my model (see below). Assuming the model is right, I'm also grateful on tips how to deal with a non-convex Hessian when trying to fit it.
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Ben
Joined: 06/20/2023
Problems with non-convex Hessian with multilevel SEM
As written in this thread, I have repeated problems with a non-convex Hessian while working my way step-wise towards a 3-level SEM with latent variables and their respective measurement items in a paper in organizational psychology.
While I'm looking for general guidelines to deal with non-cenvex Hessians and status code 5-issues in that thread, it's probably good to look at my models to find issues here.