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Questions tagged [random-effects-model]

Parameters associated with the particular levels of a covariate are sometimes called the “effects” of the levels. If the levels that are observed represent a random sample from the set of all possible levels we call these effects "random."

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Estimates radically change when including Random Slopes in Multiple Logistic Regression

I am examining the fixed effects of two within-subject experimental manipulations (i.e., Ambiguity 0 = No / 1 = Yes, and Uncertainty 0 = No / 1 = Yes) on a dichotomized variable (i.e., Punishment, 0 ...
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Mixed logit random parameters for non-alternative-specific variables

It is my understanding that in a mixed logit model there can be two types of variables, alternative specific and individual specific. For example, in a dataset for choices of fishing modes like this (...
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Compare using `lme4` and `nlme` for mixed effects models

Sorry it might be a more Stack Overflow question but I was reading this nice cheat sheet for using function lmer in package lme4 ...
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How to include covariates in a nested model?

I am new to multilevel model and having trouble understanding how to include covariates. In my mode, I have Industry and Country ...
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Interpreting BLUPs or VarCorr estimates in mixed models?

I am referring to the question. When estimating random effect (RE) variance or correlation, the estimations are different in VarCorr(mod) function and when ...
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GAMM with multiple and crossed random effects

I am new to Generalized additive mixed models (GAMM) and I'm trying to model a behavioral response variable (time spent shading eggs by a nesting bird in minutes ...
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How to fit a longitudinal GAM mixed model (GAMM)

I have repeated measurements of individuals, like this ...
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3 Level Hierarchical Models in STATA; Null model fails to converge

3 Level Hierarchical Models in STATA; Null model failed to converge About the Dataset I am working with DHS (Demographic and Health Survey Data) data. DHS uses a two-stage cluster sampling process. ...
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Are anxiety measure fixed or random factors in this scenario?

As a psychologist and not a statistician, I have always used ANOVAs to perform analyses on repeated-measures designs but have since learned you should instead use mixed linear modeling with these type ...
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Crossed or nested random effects?

I've conducted an experiment in which 20 pairs of talkers are conversing in their first and second language (L1 and L2, respectively) both in quiet and in noise in a fully crossed design: L1 in quiet ...
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Random effects vs Rubin's rule to obtain pooled parameter estimates from multiply imputed datasets

I would appreciate any help to understand the statistical difference between using random effects and Rubin's rule to obtain pooled parameter estimates from multiply imputed datasets. For example, if ...
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Treatment (equivalent to experimental groups) in Experiment as Fixed AND Random Effect in Mixed Model Linear Regression

I have data from a sociology experiment with three groups. Each group is equivalent with a different treatment for a subject (n=700). The treatment were surveys, differing in the amount of information ...
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Formula for cross-classified (a.k.a., crossed random factors) mixed effects model with interaction between two “second level” variables

I have a crossed-classified (Hox, 2010) mixed effects model—also known as crossed random factors (West, Welch, & Galecki, 2015), but I am struggling with how to write the formula for an ...
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Minimum sample size per cluster in a random effect model

Is there a rational for the number of observations per cluster in a random effect model? I have a sample size of 1,500 with 700 clusters modeled as exchangeable random effect. I have the option to ...
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R Mixed-Effect Models for 2-way Repeated Measures Design with more than 2-levels in each factor

Background: I am running an experiment with the following parameters. Design: 2-way Repeated Measures Design (as of right now there are NO between-group/grouping variables Dependent Variable: A ...
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weird assumption of one-way random effects ANOVA

$$Y_{ij} = μ \, +\, A_i \, +\,ε_{ij}$$ In Ch5 (random effects one-way ANOVA) of my textbook, it mentioned that $A_i$ (see the model above) is assumed to be $\sim N( 0, \text{constant_variance} )$ ...
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GLMM - Aleatory effects in R [closed]

I have a question if you could help me? I studied during 2 days (48 hours), 8 times per day (every 3 hours), 3 nests per species (2 species), the number of ants every 3 min that walk by a point. I ...
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Random effect in GAM - what are the smooth functions used?

In the GAM package in R created by Simon Wood there is a selection of the smooth function basis. I sort of understand the options such as bs='tp', bs='cr', etc. But bs='re' seems odd... that does ...
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Simulating survival meta-analysis data (with a random effect) [closed]

I would like to simulate survival meta-analysis in clinical trials on R but I'm not pretty sure of what would be the best way to do it and what would be fitting more the reality. The data would ...
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A few questions about the calculations behind the metabin function, part of the R 'meta' package for meta analysis of binomial data

I am new to meta analysis, and am reading about how to perform meta analysis with binomial data. I'm looking for some clarification on some of the results given by the metabin function, which is part ...
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Does a panel regression model make sense for my data?

This might be a bit of a newbish question, but I recently picked up a forecasting project at my job, and I'm trying to figure out whether it makes sense to run a panel regression like a Fixed Effects ...
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Survical model: get time-dependent survival estimates with nested random effect and repeated measurements

In an ecological experiment I have recorded survival of individuals in response to two different food items (treatment). Individuals belong to different families (random term) and are measured at 5 ...
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How can I plot fixed and random effect in a boxplot?

In case a random effect has influence on the weight of outcome variable how would I plot the corrected values? I'm not sure if "variables getting weighted by the random effect" is something that is ...
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Determining nested or crossed random effects in study design

I've found several versions of the canonical example of nested random effects about classes in schools or students in classes.. However, I'm still having a hard time connecting the school/classes/...
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Fixed/Random effects precise explanation

I read about these terms, but as I read more on internet about it I get more confused, people have discussed it in different ways and from different aspects... and still I am not confident to say I ...
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1answer
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Grand-mean centering in GLMM changes estimates for variance (and everything else)?

I know that when running a linear mixed effects model, centering around the grand mean should change the estimates for the coefficients, but not the estimate for the variance. For example, I have ...
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Marginal interpretation of fixed effects in GLMM

I understand that when applying GLMMs (e.g. in logistic mixed effects regression), the interpretation of the coefficients for the fixed effects is that they are also conditional on the random effects (...
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How to calculate the variance components in an expanded gauge R&R

I have found how to calculate the variance components for a regular gauge R&R (with just the parts and operators as the factors), but I would like to learn how to calculate the variance components ...
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Panel Data: correlation between individual effects and variables

Is it possible to see if there is a correlation between any variable and the individual effects just by looking at the coefficients and standard-errors of an OLS, RE and FE functions?
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Between subject effects with repeated measures?

I have some data with a repeated measures/replication problem, but I am not interested in within subject effects, but instead the overall effect. Can I control for this with either a mixed or marginal ...
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Non-straight lines in random intercept random slope plots

I'm trying to see how boldness of individuals change over time. For this, I constructed a repeated measures random intercept random slope model with boldness scores (measured as latency to resume ...
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Should reviews/ratings data be considered as repeated measures?

Suppose I have some ratings/review data for a type of product (say coffee). There are many different kinds of coffee and there are many different subjects reviewing coffee and also some covariates ...
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1answer
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Intercepts of repeated measures

I'm examining how boldness of individuals change with time. My data consists of individuals repeatedly measured across trials for boldness scores. First, I plotted each individual to see its mean and ...
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What's the equivalent function for mLogit() if random effects are involved? [duplicate]

mLogit is the function for running multinomial logistic regression in R. What if we have random effects (mixed-effects model), what's the adequate function (and ...
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Random slope random intercept model for two grouping levels

I'm trying to see how boldness of individuals change with time (plasticity in personality). My data consists of boldness scores (response variable), Trials (across time), individuals nested within ...
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1answer
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Intensity function in Poisson random effect model

I have a somewhat general question about intensity functions in Poisson random effect models. Consider the Poisson random effects model in which conditional on a random effect $u$, an individual ...
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Mixed effect model covariance prior

How should I choose the covariance prior for my bglmer model? This is a model which has the singularity problem. ...
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Fixed or random effects in a subgroup analysis where heterogeneity is present in one of the subgroups but not the overall pooled result?

I am looking at a meta-analysis where a subgroup analysis has been performed, as it is important to consider the treatment effect within 2 subgroups of interest, as well as the overall pooled result. ...
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1answer
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Random Regression in R

I am a student. I have some knowledge of mixed regression models. I would like to implement Random Regression in R. I found "Random Regression Models" by Schaeffer (http://animalbiosciences.uoguelph....
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The correct random slope model for nested data

I'm trying to see how personalities of individuals change with time. The variables in my data are: 1. latency to emerge (response variable in continuous scale) measured for 204 individuals from 14 ...
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Introducing random slopes in models with nested random effects

I'm trying to see how latency to emerge (response variable) is varies with time (trials). Individuals (ID) are nested within colonies. The nesting is such that individuals 1-20 belong to colony 1, 21-...
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How can i plot a linear mixed model

i have constructed a mixed model for a nested design. i have attached it below: A researcher observes variation in wing size in a beetle species in South-America and wants to know whether wing size ...
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R - How to get estimates and p-values for random effects in glmer

I have data about around 100,000 protests nested within 40 countries and I want to analyze when the claims of a protest are directed at the state, based on action and country level characteristics, ...
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1answer
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Introducing random slopes in nested model improves model fit but residuals variances become unequal

I have measured boldness scores (continuous variable) across time (trials) for individuals (ID) within colonies (colony). The data is coded such that individuals 1-30 belong to one colony, 31-60 to ...
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1answer
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Fixed Effects vs. Random Effects vs. First Differences

I'm working on a university task where I have to estimate the following using panel data: \begin{equation} y_{it} = x_{it}\beta + \alpha_i + \epsilon_{it} \end{equation} where $y_{it}$ is log($...
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Is Hausman-Taylor Estimator with different within- and between-group effects biased?

Background Assume the simple two-level linear model $$y_{ij}=\beta_0 + \beta_1X_{ij}+\beta_2X_{ij}^{end}+\beta_3Z_j+\beta_4Z_j^{end}$$ where $X_{ij}$ and $Z_j$ are exogenous and $X^{end}_{ij}$ and $Z^...
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ANCOVA vs Random effect for category

Assuming a categorical variable is a nuisance variable, why would one ever use it as a fixed effect as in ANCOVA instead of using it as a random effect? As an example consider modeling the ...
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2answers
64 views

GLMM species count data with transects

I am trying to create a GLMM model which explains differences in abundance/count of three species of scorpion around a field reserve in different forest types. -I have 7 trails in different forest ...
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A survival (accelerated failure time) regression model for censored data across several trials

I have this experimental design: Two groups A and B. Individuals from group B were genetically manipulated such that when they are given a certain drug the drug turns on a gene that was inserted ...