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Mixed Effects and Nested Models

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No user picture. caitlin2727 Joined: 06/04/2024

two-level growth mixture model

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Mixed Effects and Nested Models
Hello~

I am trying to fit a two-level growth mixture model (which is three-level LMM with two latent classes).

The subject's outcome (y0, y1, y2, y3) is nested within the subject and then nested within different centers.

##wide type
data <- reshape(indata[,c("Center","ID","Time","y")], idvar = c("Center","ID"), timevar = "Time", direction = "wide", sep = "")
centerdata= data.frame(Center= mydata3[!duplicated(mydata3$Center),1])

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Picture of user. pehkawn Joined: 05/24/2020

Mulitlevel model with ordinal data

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Mixed Effects and Nested Models
I've been trying to build a three-level analysis of student survey data on the relationships between teaching practices and cultural background (SES as covariate) on science achievement.

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Picture of user. Mike Cheung Joined: 10/08/2009

Variance components in two-level models

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Mixed Effects and Nested Models
Hello all,

I want to estimate the variance components in a two-level model. The estimated variances seem correct when there is only one variable. However, the estimated variances appear incorrect when more than one variable. The observation is that the between-level variances are under-estimated, whereas the within-level variances are over-estimated.

Attached is an example with 1,000 level-2 units, each with 100 level-1 units. This ensures that sampling error does not play a critical role.

Did I do something wrong here? Thanks in advance.

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No user picture. jpritsker Joined: 09/27/2020

Nesting with movement between clusters over time

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Mixed Effects and Nested Models
I'm considering a model where children are nested within schools, but may change schools over time. So, I have data structured as CHILDID, Y1, X1, SCHOOLID1, Y2, X2, SCHOOLID2, ...

I initially considered having a single random effect value per school, and having $y_{i,t,school} = \mu_{school} + \dots$, but I'm not sure how to index the same random effect by different variables over time (i.e. mu[SCHOOL1], mu[SCHOOL2]) in this way.

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No user picture. janajarecki Joined: 06/26/2019

Mixed-effects mediation example in openmx?

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Mixed Effects and Nested Models
Hi there,
thank you so much for developing openmx, it's fantastic and flexible.

Do you probably have an example for openmx for a
(i) mediation model in openmx, or
(ii) mediation in a mixed-effects model [at the cluster-level or the within-cluster-level]

(Couldn't find any on the page here nor google).
Cheers, and thank you!
Jana

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No user picture. Vivifj03 Joined: 04/25/2019

Two-parts mixed effects model for longitudinal data with mixture distribution for random effects

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Mixed Effects and Nested Models
Hi you all,
My outcome variable is a semicontinuous variable measured over time with a bunch of zero values. Since it is continuous data I cannot use poison or other zero-inflated models. However, I am implementing a two-parts model. The first part is a logistic mixed effects model for modeling the zero currency. Then, the second part is a linear mixed effects model. Now, there are two main issues. First, the random effects of both models are correlated. Second, the distribution of the random effects is a mixture of normal distributions.

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No user picture. dcep Joined: 12/11/2018

Postulating mixed effects model with random intercepts and slopes

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Mixed Effects and Nested Models
Could you please help me translate the following model in the picture to OpenMx syntax using path specification?
Latent variables depict latent intercepts and latent slopes.
I am a beginner in OpenMx and need to check the model urgently.
I would be really grateful if you could help.
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No user picture. cdmcdermott221 Joined: 10/09/2018

Multilevel, longitudinal model (3-level model)

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Mixed Effects and Nested Models
Hello all,

I know similar questions have been posted here but I'm still unable to figure out the code for my model, as I am super new to OpenMx and structural equation modeling in general. I have intervention data collected at three time-points on children nested within schools. I would like to look at the effect of the intervention over time for the children, but taking the clustering from the schools into account. I'm trying to get my structural equation model to match this mixed model from the nlme package:

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Picture of user. forscher Joined: 03/05/2013

Combined multi-group and multi-level SEM

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Mixed Effects and Nested Models
I'd like to test whether the variation in the average responses given by participants(the so-called "random intercept" in multilevel model terminology) is different across levels of a specific grouping variable. This seems like something I should be able to do in OpenMx, but I can't figure out how. Specifically, I'm stumped on how to combine multi-group SEM with multi-level SEM, even though I know OpenMx can do each of these separately.

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No user picture. mediation Joined: 05/30/2018

Multilevel 3-2-1 Mediation Model

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Mixed Effects and Nested Models
Hi,

I am new in OpenMx.
Can OpenMx handle a 3-2-1 mediation model? Do you have any example codes for this?

Claire

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