Behavioral Genetics Models
szellers
Joined: 04/04/2018
Standardizing factor loadings
I am working with a common path model and I am having difficulty standardizing my factor loadings. In the past, I have identified the model by constraining the variance of the latent phenotype to 1, then I standardize factor loadings by using a matrix of standard deviations (SDs on diagonal, 0s on off-diagonal) and multiplying that by the matrix of the unstandardized factor loadings (I can attach code for this if necessary)
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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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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.
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()
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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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.
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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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).
Fengxia
Joined: 11/02/2017
Bivariate twin model（ACEorADE）
Hello,
Recently, I have done a bivariate models.BUT I am confused with how to choose ACE or ADE in the bivariate models? I have tried using ICC in each variable apartly, BUT the fitting model one is ACE when another is ADE. NOW the question is that which one bivariate model I should use ? ACE-ACE or ADE-ADE or ACE-ADE? If the the answer is ACE-ADE, how to write the script?
Thanks for some help!
Cheers,
Fengxia
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oscarrob
Joined: 03/10/2018
Twins raised apart + together
Ciao all,
I do not know if this is the most appropriate section for posting however I will give it my best shot. I am conducting a capstone project for my genetic epidemiology program but unfortunately my mentors are unaware of the methods used for the project I will describe here so they encouraged me to connect with individuals on this website. Some may argue I should do a project that I can receive some assistance with from my mentors but I am passionate about this project!
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