Behavioral Genetics Models
lior abramson
Joined: 07/21/2017
bivariate Cholesky descomposition for dummies
I have a longitudinal dataset on twins at the age of 6 and 9 years. For the purpose of examining change and stability in genetic and environmental effects, I would like to conduct a Cholesky decomposition analysis, allowing girls and boys to differ in their ACE components and including one categorical covariate in the analysis.
- Read more about bivariate Cholesky descomposition for dummies
- 1 comment
- Log in or register to post comments
chancey
Joined: 09/09/2017
95% CIs for Univariate models.
Hi all,
I am relatively new to the OpenMx environment and was looking for feedback on a problem. Specifically, I am working with a series of univariate ACE models for ordinal variables in OpenMx using code from here.
- Read more about 95% CIs for Univariate models.
- 2 comments
- Log in or register to post comments
Kelsey
Joined: 01/31/2017
lior abramson
Joined: 07/21/2017
how to choose between ACE, AE, CE, and E when only E is significantly worse than ACE?
I have a relatively large dataset (500 same sex twin pairs) where the raw correlations of the observed phenotypes between MZs and DZs show shared environment effects (e.g., MZ-.39 vs. DZ-.29). Moreover, if I enter only these correlations into a script in the old Mx program, I get significant shared environment effects.
tbates
Joined: 07/31/2009
NAs in definition variables
Here's a [test file](http://openmx.ssri.psu.edu/sites/default/files/NA%20def%20test.R), which allows you to create data in a twin model with covariates on the means, either including, or excluding rows that are NA on the definition variable.
With NAs in the def vars, it runs (under OpenMx version number: 2.7.12.47), but the results appear to be the start values.
[Question 3](https://ibg.colorado.edu/dokuwiki/doku.php?id=workshop:2016:questions) in the IBG forums is relevant to this also.
- Read more about NAs in definition variables
- 1 comment
- Log in or register to post comments
JuanJMV
Joined: 07/20/2016
doubt with missing data
- Read more about doubt with missing data
- 6 comments
- Log in or register to post comments
lior abramson
Joined: 07/21/2017
Univariate ACE models for males and females separately (Heterogenous model)
lior abramson
Joined: 07/21/2017
centering variables in a univariate ACE model?
I would like to perform a simple univariate ACE model with three covariates (one continuous and two binary).
Is there a need to center any of the variables before approaching the analysis? there are no interaction effects in the model so my hunch is that I don't need to do it, but I would still like to ask to be sure...
Thank you!
lior abramson
Joined: 07/21/2017
script for ACE model with covariates using paths specification
Does anyone know where can I find a reliable example of an openMX script to an ACE model with covariates (e.g., age) using path specifications? I saw that there is an example with matrices analysis, but since I only now begin to get my hold on openMX, I would like to understand the syntax of paths analyses before jumping to a new method...
Also,do you know on some kind of a workshop (somewhere in the world or online) that teaches openMX and twins analyses from the beginning?
Thanks!
lior abramson
Joined: 07/21/2017
Starting values in a univariate ACE model
I am very new to twin analyses in general, and even newer to openMX.
I have tried to perform a simple univariate ACE model using paths specifications. I followed the example called "ACE model: A twin analysis" (section 2.5.1) in the openMX user guide.
- Read more about Starting values in a univariate ACE model
- 1 comment
- Log in or register to post comments