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Hi Everyone,

I have a more general question about MZ and DZ correlations and their relationship with the Chronbach's alpha of the questionnaire that is used.

I am running different twin models to estimates A,C and E contribution to variation in behaviours using a parent measured questionnaire in a sample of infants and toddlers.

When running the analyses I am consistently finding large MZ correlations (0.80-0.95) for the different traits, which exceed the chronbach's alpas of the scale.

I'm currently runnning a three variable Cholesky ACE model and am able to grab CI's for my variance estimates and correlations but my model crashes and gives me an NLOPT fatal error -1 when I attempt to retrieve confidence intervals for covariance estimates. I'm wondering if anyone can tell me why and how to retrieve the problematic CI's. Here's my script:

# -----------------------------------------------------------------------------------------------------------
# Script: 2ACE_Chol.R

# Fits a MV Cholesky ACE Decomposition
# Data File: Covariate Regressed Cross-trait Data.csv

Hi all,

I noticed in the ADE code (http://www.vipbg.vcu.edu/HGEN619_2014/twinAdeCon.R) that the only submodels considered are AE and E models. I would like to ask: why isn't the DE model a possible model to consider?

Thanks and best regards,
Yi Ting

Hi all,

I tried to modify the heterogeneity model for MZM, DZM, MZF, DZF and DZO groups to include covariates. I got the following error message when I tried to run my code:


Running QualACE
Error: Unknown reference 'expMeanGf' detected in the entity 'expMeanGfm' in model 'DZo'


May I know what changes should I make to my code to run it successfully? My code is as follows:


require(OpenMx)
require(psych)