Generalized Linear Mixed (effects) Models are typically used for modeling non-independent non-normal data (eg, longitudinal binary data).

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single group pre/post test

I have a single group pre/post test design. I am estimating a GLM with baseline covariate, along with a vector of other covariates. The goal is to assess change in the outcome. I found a significant ...
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24 views

Help with zero-inflated generalized linear mixed models with random factor in R

My study has a complicated design and I am not sure if I am modeling my zero-inflated data correctly (and no one I have talked to in person knows either). I have seed abundances and seedling ...
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9 views

Strange predictions from binomial glmm?

I am analysing the dominance of a Species, i.e. its relative abundance in a community. Since these data are proportions I use binomial models. However, the predictions from these models are ...
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20 views

Impact of unweighted data on technical model validity

I would welcome views on whether a repeated-measures analysis on unweighted survey data would be sound. I am interested in the internal dynamics between model covariates and the dependent variable, ...
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10 views

How to interpret glmmPQL summary value

I'm doing a GLMM with quasi-Poisson to check for a spatial correlation between some predator bugs and their prey (count data of predator and prey + added distance of plots). I've added everything into ...
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10 views

Predictions from Poisson GLMM (lme4) lower compared to GLM

I am modelling visitor counts to a sample of sites in a forest in order to predict the number of visitors to the rest of the forest. My predictor variables are time of day (categorical), day of week ...
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1answer
21 views

Quadratic term and categorical predictors

I have a quick question about the use of quadratic term in GLMM. Can I use it with categorical variables? I read somewhere that its use is restricted to continuous predictors and the thing is that I ...
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1answer
28 views

Confidence bands for model averaged predictions of GLMMs

I use R with the MuMIn package for Multimodel inference. my global Model is ...
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15 views

Nested random factors in GLMM: use them or drop them?

I am a new R user running into GLMM models. I have some data of frequency of pollinators in crop fields adjacent to forest fragments, with the following experimental design: 4 forest fragments, 2 of ...
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91 views

Alternative to GLMM for normalised ratio (Bounded: -1 to 1) response variable

My response variable is a metric calculated from the normalised ratio of two variables. Calculated as (a-b)/(a+b), resulting in a normalised ratio of continuous data bounded between -1 and +1 - my ...
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1answer
62 views

Random effects model for a derived variable - how to use the data

My data is a series of measures for a biological trait ($Y$ - e.g. weight, height, length, running speed) from multiple populations ($n$ = 2), taken over a number of years, in males and females of a ...
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32 views

Linear Mixed Effects Model [closed]

I have data with some of the following columns: Site (categorical, 1-4), Species (Categorical, 1-21), Damage (continuous), and Age (categorical, 0-6). Age represents the visits to each site where I ...
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31 views

glmer() error: response is constant

I am trying to run a GLMM for a resource selection analysis using the lmer4 package in R. The model contains a binary response (used/unused), five continuous variables (distances to features), and a ...
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24 views

How should I interpret/follow-up on mixed logistic regression (GLMM) diagnostics?

I have experimental data (n subjects = 64) in which the response variable, accuracy (0 or 1), was measured 9 times within subjects. My predictor is Condition (A vs B) measured between subjects. I ...
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13 views

Under-dispersion in a GLMM with Bernoully outcome

I have a GLMM for my data (collected for an urban tree research), wich include the next variables: Outcome: 1 inffected, 0: no inffected Treatments 1 and 2 (like dummie variables) T1 and T2 Species ...
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1answer
25 views

underdispersion in a binomial GLMM

I am trying to analyze data from an experiment in which I measured the learning of a colour preference in birds under two treatments. 40 Individuals were organized into 8 groups, and 4 groups were ...
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1answer
40 views

glmer with binary response variable: how to select fixed effects?

I have measured nest building (building / not building) 5 times over the breeding season and want to see if there is an effect of my treatment (treated / control). After selecting random effect with ...
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1answer
136 views

How to test equivalence of two models using MSE?

I want to compare two generalized linear mixed models (GLMM), model A and model B, which differ from their link function. More specifically, I want to test wheter these models are equivalent or model ...
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8 views

How to handle with a very small sample and unbalanced dataset? Is GLMM a good option?

I'm having some troubles in analyzing and make the most of my dataset. My hypothesis: pharmacological condition maximizes utility of the decision regardless of the context (by providing the necessary ...
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13 views

How to handle with unbalanced and small sample dataset? Is GLMM a good option?

I'm having troubles in analyzing and make the most of my dataset. My hypothesis: pharmacological condition maximizes utility of the decision regardless of the context (by providing the necessary ...
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19 views

Inverse Gaussian with MCMCglmm in R

I am trying to specify a mixed model using the MCMCglmm package/function in R. My data follow an inverse gaussian distribution, so I want to use MCMCglmm as an alternative to using an inverse ...
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1answer
78 views

GLMM or LME? Repeated measures help?

I am having trouble using the correct test and r code for my experiment. Essentially I measured insect emergence daily from artificial streams with 3 treatments.: ...
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1answer
41 views

Interpreting the residuals vs. fitted values plot for logit GLMM?

What I have is a generalized linear mixed model of the log OR of a rater (random effect) giving a response above a certain level on an ordinal scale, given a specification of what the rater was ...
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52 views

When you have a multilevel / mixed effects model, how do you incorporate the random intercepts when making a prediction?

When you have a multilevel / mixed effects model, how do you incorporate the random intercepts when making a prediction? Here is the context: I'm trying to model a Bayesian regression using an index ...
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31 views

data visualization following glmm in lmer

Everything I know about glmms is from the internet, and after extensive searching, I haven't come across a good clearcut guide for how to visualize your data in a way that is relevant to hypotheses ...
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32 views

SPSS: GLMM and(adjusted) odds ratio

I am performing a retrospective study and the relative statistic analysis. I am studying the the risk factors for the occurrence of complications during medical procedures. I have 50 subjects ...
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57 views

Shall I use a random effect or not?

I need to see if in the case I am going to present it is worth to use a random effect or not. I carried out some bird counts from 9 elevated lookouts in an island. Just to orient you, these lookouts ...
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20 views

Determing Probability Distribution of PCA Values

I am trying to determine the best distribution for PCA values. I did an experiment where I have a lot of response variables and I think they're best interpreted through using a PCA. I want to use a ...
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22 views

What test to use for non-parametric repeated measures data?

I've been having trouble finding the correct test to use for my data. I measured the response of subjects to two treatments across three different time periods (e.g. beginning, middle, end). I want to ...
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46 views

Which test to use for matched case-control setting with repeated measures and a continuous outcome?

I apologize if this question has already been answered in the past; I was unable to find a similar setting by searching. I have a study with 2 groups (rare cases and their siblings, N=13+13). Each ...
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102 views

Crossed fixed effects model specification including nesting and repeated measures using glmm in R

Background: I am interested in looking at the effects that Culture, Treatment and Time ...
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15 views

Marginal vs. Conditional Model

I have a question regarding GEE vs. GLMM. I know the probabilistic difference (marginal vs. conditional). What I want to ask, is when should I use each one. More specifically, in clinical trials, is ...
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15 views

R-Side GLMM vs. GEE

I wanted to ask what is the difference between an R-Side mixed model (with a binary outcome) and a GEE ? People often call an R-Side GLMM a "GEE type" model, but it ain't a true GEE, since it has also ...
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1answer
147 views

Nested random effects in lme4 R

Background: I have data on time to infection across multiple sites across a gradient. The design involves 2 latitudes (In and Out) with sites 1 and 2 nested within “In” and sites 3 and 4 nested within ...
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45 views

Poisson glm for rank or score data?

I have a question about analyzing a dataset that I'm currently working with. Each row of the dataset represents an individual songbird, and its reproductive success over the course of a breeding ...
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39 views

Modeling Correlated Binary Data

I have data which looks like this: Subject ID (unique identifier), Group (Treatment or Control), Eye (Left / Right), Outcome (Success / Failure). The data is coming from a trial testing a new ...
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1answer
57 views

How to account for a lack of fit using a quasi-poisson on non-integer, overdispersed data

I am trying to run a mixed model on over-dispersed non-integer data. My data are not counts, but are zero-inflated and over dispersed. The variable is distance (how far a gps point is from a central ...
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10 views

modelling costs with meglm: error message on zero values

My dataset has repeated observations on patients with patient-level costs captured at regular intervals over a period of time. I model how these costs vary over time using time-invariant patient ...
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1answer
83 views

Interpretation of covariance estimates glmm (proc glimmix)

I am using the glimmix procedure in SAS to model a generalize linear mixed model with and binomial distribution and a logit link function. I am modeling both the G-side and the R-side covariance ...
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73 views

Set G in prior for MCMCglmm in R

I am new to the MCMCglmm package in R, and rather new to glm models in general. I have a dataset of species traits and whether or not they have been introduced outside of their native range. I would ...
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21 views

How to construct model for GLMM with repeated measures?

I'm trying to construct a model using a GLMM for my data. I performed an experiment where I exposed different subjects to 2 different treatments between 3 and 7 times (depending on the subject) during ...
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32 views

GLMM Multilevel Model

I had posted 1 year ago this post : GLMM multilevel (hierarchical) model My model is now a bit different. Nowadays I want to study the classroom, the teacher and the school effect on the pupil's ...
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63 views

GLMM or LMM with transformed data

I have a response variable that is the absolute value of a difference between two proportions. The distribution looks like this: I also have two values for each of 20 individuals, so I need to use ...
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491 views

Diagnostics for generalized linear (mixed) models (specifically residuals)

I am currently struggling with finding the right model for difficult count data (dependent variable). I have tried various different models (mixed effects models are necessary for my kind of data) ...
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45 views

Advantages and Disadvantages of GLMM and GEE

I am making a list of disadvantages of GEE and GLMM for a correlated binary outcome. So far I know that GEE requires a relatively large number of clusters, and that it produces profile curves that ...
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26 views

Which model to choose: GLMM or GEE?

I have data with a binary outcome (success/failure) and a binary explanatory variable (treatment/control). For each subject (this is a clinical study), I have two observations, coming from two eyes. ...
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1answer
26 views

Multilevel models vs GLMMs for correlated clustered data

What is the difference between the Generalized Linear Mixed Model (GLMM) and a multilevel model?
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42 views

GLMEM vs LM on proportions within random effects

I'm doing a project involving outcomes measured for people clustered within departments. The departments had previously been randomized to a treatment or control condition. One of the main outcomes ...
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27 views

GLMM for repeated longitudinal count data

I have multiple longitudinal data sets (3 repeat trials) of microbial count data for a cohort of animals (each trial had different animals); animals belonged to either a treated or untreated group and ...
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1answer
56 views

linear mixed model with 3 group categorical response

I've been looking all around the webs but cant find a conclusive answer. I have count data for a longitudinal study where subjects were grouped into three treatment groups (A,B,C) and blocked by ...