OpenSEM Forums

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Picture of user. Julia Joined: 03/29/2012

Bootstrap CI's for algebras

Hi.

Is it possible to get bootstrap confidence intervals for algebras? I am running a trivariate CHolesky decomposition model on binary variables and estimating CI's through mxCI takes more than 24h. When I ran mxBoostrap, I got CI's only for model parameters, but not for algebras. Is there a way to specify it? Or is there a way to reduce the time to running a model with intervals=T?

Thank you in advance!
Julia

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Picture of user. gary.marks@acu… Joined: 07/14/2016

Multivariate Independent Pathway with Multiple Occasions

I have been analyzing achievement/cognitive test data from the NLSY79 Children data set. I have constructed sibling-cousin pairs for each of the five tests (PPVT, digit memory, reading comprehension, reading recognition and math) at 5 occasions (ages 5-6, 7-8, 9-10, 11-12 &13-15). I have successfully run a independent pathway model for domain scores averaged over occasions (zero to 4) and 5 separate models for each age. However, there are several reasons why a combined model using all the data is more desirable than running separate scripts for each.

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Picture of user. tbates Joined: 07/31/2009

confidence intervals in a common pathway model (with constraint)

Reviewers have requested I give confidence intervals on estimates from a common pathway model (I am using the `umx::umxCP` function to build my common pathway model).

When I try and use Hunter's nice `mxSE(top.es_std[1,1], model = cp3)` function on to request the SE on the specific-e for variable 1), I get the following error:

Model does not have a reasonable Hessian or standard errors.
Model has at least one mxConstraint. This prevented standard error computation.
Try mxCI()

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No user picture. Aurina Joined: 01/05/2016

Including covariates to saturated model

Hello,

I'm trying to run an ACE model for some imaging-derived measures and hope you could help me to solve some of the issues.

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No user picture. Veronica_echo Joined: 02/23/2018

bootstrap likelihood ratio test (BLRT) for GMM with definition variables

Forums

Hi everyone,

I would like to conduct BLRT test for 2 nested GMM model with definition variables. I referred to a previous post
https://openmx.ssri.psu.edu/node/4329 and it worked well on my computer. However, when I run the comparison of my model, it reported errors. I attached a screenshot of LRT without and with bootstrap in the attachment. And here is the information of my OpenMx Version:

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No user picture. szellers Joined: 04/04/2018

Latent Growth Curves and Definition Variables in a Twin Sample

I am trying to fit a latent growth model in twin data and I am having trouble writing code for definition variables. I want to fix the loading from the intercept to the observed vars to 1 and I want to use age at assessment as the loading for the slope. This model runs when I use just a number corresponding to wave (1, 2, 3, 4, 5) for the slope loadings, but I am having errors when trying to use the definition variable of age at each assessment as the factor loading for the slope. My code here fails at the flValues line.

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No user picture. JuanJMV Joined: 07/20/2016

Longitudinal Question

Hi,

I am considering using a bivariate model to investigate the relationship between variable 1 and variable 2. Data is available for both variables for the same population for 2010 and 2016.

If I want to investigate this relationship longitudinally (the effect of variable 1 on variable 2) could I use a bivariate script with variable 1 in 2010 and variable 2 in 2016? or should I use a different model/script?

Thank you so much.

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Picture of user. mhunter Joined: 07/31/2009

Pre-conference Short Course on Dynamical Systems

Hi All,

Sy-Miin Chow, Michael Hunter, Charles Driver, and Peter Molenaar are teaching a 1-day short course on "Continuous- and Discrete-Time Dynamic Modeling in R" as part of the Psychometric Society conference on July 9th in New York City. The course will use - among other software - ctsem which interfaces to `OpenMx`. More details are on the Education page. Below is the workshop abstract.

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No user picture. lior abramson Joined: 07/21/2017

Bivariate Cholesky model with paths specification

Dear Forum,
I wrote a syntax for bivariate cholesky model for two variables measuring two different traits at the same time-point. However, I think that I may have missed something. In the output I see the ACE coefficients for each observed variable, but I do not see the the ACE coefficients to the covariance between the two traits (i.e. the coefficients that explain what part of the variance is explained by shared genetic and environmental influences on the two traits).