OpenSEM Forums
Aivil
Joined: 03/14/2019
Help in understanding notation for NO-GROWTH MODEL (OpenMx) and ERROR message
Hello,
I´m having a hard time understanding the OpenMx notation from this handbook "Growth Modeling" (Grimm, Ram & Estabrook, 2017).
The authors compare the script from MPlus and OpenMx with regard to the specification of a no-growth model (attached as pics). While in Mplus is pretty straightforward, I don´t understand why the latent factor variance (psi_11) and the indicators residual variances are set at 80 and 60 respectively in the OpenMx script.
Qiuzhi Xie
Joined: 12/27/2018
G*E interaction with a moderator
I am currently doing G*E interaction with SES as a moderator. The plot (attached here) suggests that SES likely moderates with the A factor. To analyze whether the moderation effect is significant on A factor, I drop the moderator on the Path A only and compare the model fit (diffLL). I find that the p value is insignificant. I want to ask whether this is the correct way to see the significance of moderator effect.
Also, is it appropriate to see the unstandardized variance components by SES moderation, rather than the standardized variance components?
- Read more about G*E interaction with a moderator
- 4 comments
- Log in or register to post comments
Julia
Joined: 03/29/2012
Nonlinear transformation and estimates
Hi. I have a question about analysis of non-linear transformed variables. I have a continuous variable which is skewed (1.2). Box-Cox transformation suggested 1/y transformation. If I run ACE models (and saturated) on this new variables, how do I interpret and report the results? Is it common to report the estimates for the transformed variable? And is it possible to get the estimates for the original raw variable then?
Thank you in advance!
Julia
- Read more about Nonlinear transformation and estimates
- 3 comments
- Log in or register to post comments
ethibodeau
Joined: 05/16/2018
More questions about the magic of LGM with use of age definition variables
Either SEMNET is not getting my emails or they don't care about my questions (probably the latter), so I'll ask them here specific to OpenMx.
ZR
Joined: 07/26/2017
How are weights used in mxData
Hi,
I couldn't find a in depth enough explanation in the documentation and I don't know c++ to be able to get this information from the source code, but I just wondered if anyone can expalin exactly how the weights in the "weights" argument in mxData is actually used mathematically? I know obviously a bigger weight will give more weight to that row of data etc, but I wanted a more detailed explanation than this if that's possible?
Thanks!
- Read more about How are weights used in mxData
- 3 comments
- Log in or register to post comments
rranne2@uic.edu
Joined: 12/10/2018
links are down
I tried to use the link to learn more about Multiple Groups under the Features tab on this website, but the link was not active. It was not able to load the page. Is there a way to put that page up again or post that information somewhere on this website? Thanks!
- Read more about links are down
- 3 comments
- Log in or register to post comments
rranne2@uic.edu
Joined: 12/10/2018
multi group comparisons in RAM
Hello! I'm very new to R and OpenMx. I recently successfully ran a model I was interested in with a lot of pathways. The next step in my data analytic plan is to test whether the strength of all these pathways in this model are different for men and women. I was told I could use multi group analyses in order to test this. I planned on building an identical model for men and for women allowing gender to vary, and then constricting gender pathways to 1, and compare these two approaches. However, I haven't found any examples yet of someone who has done this.
- Read more about multi group comparisons in RAM
- Log in or register to post comments
Qiuzhi Xie
Joined: 12/27/2018
Question about Confidence Interval for Standardized path coefficients (multivariate model)
Hi everyone, I am new here and learning OpenMX. I have a problem of getting confidence interval for standardized path coefficients. Could anyone please provide me the OpenMx language about this? I also provide my scripts below and hope someone can let me know what the problem is (the script about 'ciACE <- mxCI("VC[1:5, 16:30]")' ) or how to read the output about standardized CI.
# Load Data
nl <- read.csv(file="C:/R/TwinPairACE.csv", header=TRUE, sep=",")
Veronica_echo
Joined: 02/23/2018
If cross-validation available in OpenMx
Hi everyone,
I would like to use k-fold cross-validation to select the # of latent classes in finite mixture models. I am wondering if some functions in OpenMx support it. And for the cross-validation part, the only things I need are -2ll and information criteria such as AIC, BIC..., and status codes (i.e. the indicator of convergence). Is there any way to speed up this process? Thanks in advance.
- Read more about If cross-validation available in OpenMx
- 9 comments
- Log in or register to post comments
KB
Joined: 12/19/2018
Latent Profile Analysis / Finite Mixture Model
Hi,
I have been following the other post about latent class analysis using EasyMx [https://openmx.ssri.psu.edu/comment/reply/4282/7227](https://openmx.ssri.psu.edu/comment/reply/4282/7227). I still have some questions and concerns. My goal is to run a two component finite mixture model (aka Latent Profile analysis with two classes).
Is the optimization being done gradient descent or some other algorithm like EM algorithm. I would like to be using the EM algorithm.