Refers to Generalized Estimating Equations which is an approach to estimating regression coefficients. GEE can be used on clustered/longitudinal data and has the attractive property that it provides consistent estimators of regression coefficients and unbiased inference even when the association ...

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7 views

Use clustered S.E. or FE/RE for binary data in an experimental within-subject design?

I am analyzing a 2x2 experimental within-subjects-design, i.e. I have data from all subjects for all four possible treatment combinations. Lets say treatment X has states X1 and X2 and treatment Y ...
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11 views

longitudinal data with changing skew over time

I want to examine a group by time interaction in a pre-post treatment study. Initially, symptoms are high so the skew is positive. But at the end of treatment the symptoms are low, so the distribution ...
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21 views

Large samples and the p-values almost zero in GEE models

I’m trying to find correlations between some environmental variables and a binary variable, berried/not berried females (rock lobster). I have 20 years of data that were sampled on a daily basis, ...
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1answer
40 views

General estimating equation with zero-inflated continuous data in R

I'm running a General Estimating Equation using the geepack package in R. I'm wondering what distribution family would be appropriate for my data, which are zero-inflated and continuous. I would have ...
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14 views

What is the appropriate link fucntion in GEE for longitudinal data where distribution changes in time?

I'm modeling treatment outcome data in a GEE with Group, Time, and their interaction. At baseline everyone is highly symptomatic, thus the distribution is negatively skewed. At follow up most people ...
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9 views

Generalized Estimating Equations with independance correlations structure versus quasi-approach versus negative binomial glm

I would like to know when it is appropriate to use a GEE with an independence working correlation structure, particularly in regard to a data set I am analysing. I have data on pollinator visits, ...
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26 views

Specifying distribution in generalized estimating equation GEE

GEE allows you to identify the distribution of the outcome variable and appropriate link function. How do you make this selection in a longitudinal model where the distribution changes in time. An ...
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11 views

Modeling change over time when response variable has different range and variance?

Some background: I am working with data from a large cohort study. My outcome is a measure of fine motor skills, and was adapted from a psychometrically validated instrument (the short version ...
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22 views

How to analyze nested, repeated and unbalanced questionnaires where the outcome is binary?

Background: My data was collected once a year for 6 years using the same questionnaire. All responses have a person-specific ID. 18 554 responses from 5 654 unique persons were collected from 7 ...
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29 views

Score test or tests based on empirical standard error estimates in Logistic Marginal Model?

I am trying to figure out whether to use a score test the other test (I think it's a test based on empirical standard error estimates?) when looking for the effect of a continuous variable in a ...
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22 views

How are complex sample analysis and GEE different from each other?

I am currently analyzing a national survey data. The survey design is complex: 1) strata 2) cluster 3) 2-stage, 4) sampling weight. There are strata; PSUs(agencies) were selected randomly and ...
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20 views

Generalized Estimating Equations- How many predictor variables are too many based on sample size?

I am conducting analyses on wild animals, on how diet of an individual changes based on environmental changes. I will list the setup of my dataset below. Until now, I have been running independent ...
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1answer
35 views

GEE/Mixed model can i use time as a factor variable?

I have data on a compound measured on 1) 0 min, 2) 10min, 3) 60min, 4) 1day and 5) 2months. i have coded these time points as 1,2,3,4 and 5, the compound has a cubic function in time when modeled on ...
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24 views

geeglm not recognizing clusters

I am fitting a geeglm model and it is not recognizing the clustering. my model is ...
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65 views

GEE as alternative for Linear Mixed Models

A linear mixed model requires the residuals to be normal. In the case of a simple linear mixed model with a random intercept only, a colleague of mine was arguiing that I could just use a GEE with an ...
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34 views

Graphing GEE Models in R?

I am currently working on a biological dataset where I am attempting to fit a detection function (Detection probability as a function of distance). I have been using the package geepack (in R-studio) ...
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30 views

covariance matrix of residuals from a fitted model to decorrelate residuals

I fit a geeglm model with clustered data and now I would like to decorrelate the residuals of the model in order to run model diagnostics. I read that if I can obtain the covariance matrix of the ...
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33 views

geeglm Model matrix is rank deficient after scaling the predictors?

Trying to run a linear regression with repeated measure using geeglm. Here is my original model: ...
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80 views

What to use when chi-square independence assumption is violated

I'm trying to describe the characteristics of the sexual partners of each participant. There are multiple partners per participant. All of the variables in my analysis are categorical, so originally I ...
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63 views

GEE and post hoc comparisons

I am trying to analyze a dataset using the GEE. This is what I have so far ...
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61 views

GEE with exchangeable working covariance vs. GLM and using Clustered Robust standard errors?

I'm analysing a dataset including 100 individuals. These 100 individuals provided self-reported depression sores on equally spaced 4 occasions (every three months). The main independent outcome is ...
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1answer
78 views

Can someone look at my method for fitting a GEE to my data?

I’ve been doing some statistical analyses in R on some data. It’s for use in a manuscript I’m hoping to get published in a biological journal. Unfortunately, the tests I ended up having to run are ...
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23 views

Contradictory results in GEE with or without a covariate

Three independent variables, one is between-group with 2 levels, the other two are within-group with 2 and 4 levels respectively. Another continuous variable (IQ) is controlled as a covariate. The ...
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58 views

GEE model for repeated skewed outcome and group mean centered time varying covariates

I have used GEE approach (log link with gamma distribution) to explore factors that are associated with outcomes of interest. My primary outcome of interest is highly skewed costs associated with an ...
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123 views

GEE in SPSS: the case of ever-decreasing QICc values

I've been using GEEs in SPSS 22 to analyze my dissertation data and have discovered an interesting problem: when trying to figure out which subset of model factors have the lowest QICc, and therefore ...
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84 views

geepack: parameter estimates change sign depending on correlation structure

I'm working on a dataset with the following variables: ...
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28 views

GEE Repeated Measurements: Specifying Measurement ID

Say I have 10 subjects, coming from three groups. In each subject I make two measurements (one on the left, one on the right). ...
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3answers
80 views

How to analyze this messy design?

I need to analyze a data-set, with a very messy design, I am not sure how. I will try to make it simple. A new kind of stitches was invented, and is tested vs. 2 old kind of stitches. I will call ...
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1answer
67 views

Cluster size in generalized estimation equation (GEE)

I'm using the gee() function from the gee package in R. The problem I'm having is that the 'Maximum cluster size' that I get ...
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20 views

How to do and interpret a generalized estimating equation

My study is looking at the effects of enclosure type (1 IV (penned v not penned)) on the stereotypical behaviours and interactions (2 DV's (counts)) of elephants, however using rain (yes/no) and high ...
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2answers
246 views

Multinomial logistic regression with geepack in R

I am working on fitting a GEE model to a multinomial logistic outcome using the R package geepack. My understanding is that the package uses ...
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68 views

Can use an interaction between time and Time-varying-covariate in mixed model or GEE?

I have a data like this: Subjects Y Day X ID1 30 0 0 ID1 40 1 0 ID1 60 2 1 ID1 70 3 0 ID2 20 0 0 ID2 40 1 1 ID2 50 ...
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1answer
484 views

How can I estimate model predicted means (a.k.a. marginal means, lsmeans, or EM means) from a GEE model fitted in R?

I am trying to obtain model-predicted means and CI's for a categorical predictor in a GEE model fitted with the geeglm function (geepack package). The model is fitted with no problem, but where I am ...
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45 views

Naive vs. robust variance in GEE

I'm analyzing a data set including 40 participants. Each participant played a decision-making game 80 times. I am using a GEE analysis clustered by participant, with an exchangeable working matrix. ...
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175 views

fitting an exponential decay onto a regression line

I have data for adherence to medicines which follows a downward linear trend for about 6 months (from 100%) and then plateaus at about 50%. Another way of describing it is by saying that adherence ...
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1answer
225 views

Statistical Power of ROC/AUC Test with non-IID Samples :: To how many IID Samples are my non-IID Samples Equivalent?

I've been assigned to solve the following problem as part of a serious, biological research project. I think I have a tentative solution, but I'm wondering whether the approach I've picked is the ...
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1answer
176 views

What are the Mild Regularity Conditions in the context of GEEs?

I was reading the Wikipedia Article on Generalized Estimating Equations, where I came across the following sentence: Parameter estimates from the GEE are consistent even when the covariance ...
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101 views

Is this longitudinal data too complicated for GLMM or GEE?

After writing this post, I've realized that I am running around in circles, chasing my tail. Any help approaching this problem would be greatly appreciated, as I think I just need to bounce ideas ...
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1answer
34 views

Repeated measures design with measurements from different groups of animals

In a repeated measured design we measure a particular variable at different time points from the same subjects. In animal experiments, if animals are sacrificed at every time point to measure a ...
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1answer
173 views

Missing at Random Data in GEE

For a continuous outcome being analyzed using GEE with a linear link, you have assurance that standard errors and point estimates are consistent with a first order trend regardless of distribution of ...
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104 views

Interpret scale parameter from GEEGLM output in R

In GEE, the variance of each outcome is equal to the variance function multiplied by the scale parameter. For a continuous outcome the variance function =1. I understand that the scale parameter for ...
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1answer
131 views

Random or fixed effects in a GLM, or perhaps GEE?

I am involved in the analysis of the effect of an intervention at five different hospitals. The intervention aimed to increase the use of a particular equipement when treeating a patient, so the ...
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1answer
99 views

Weird looking binned residual plot

My binned residual plot is quite strange looking, the 95% confidence lines are so very jagged, with points between. I have colored this "inside" of the 95% confidence interval because it is really ...
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67 views

Marginalized local odds ratios structure in GEE

The ordLORgee command from the multgee package in R has an argument LORstr. With this argument the user can specify the ...
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49 views

GEE Combined with Linear Mixed Model

Suppose we have a linear mixed model with outcome variable $Y_{ij}$ and covariate $X_{ij}$. In particular, suppose we have a random intercept model: $$\mathbb{E}[Y_{ij}|b_i, X_{ij}] = \beta_0+b_i+ ...
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1answer
47 views

Combining Regression Equations

Suppose we are interested in English scores ($E_{ij}$) and Math scores ($M_{ij}$) in students in various classes. The scores are in different scales from each other. We perform two linear regressions. ...
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27 views

Number of cluster samples in GEE

In GEE, if you increase the number of clusters would this increase or decrease the standard errors of the regression coefficients? Would the estimated std error of the regression coefficients be ...
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1answer
303 views

Interpretation of GEE coefficients

Suppose blood pressure is a continuous outcome variable and you run a linear GEE with following predictors: age (years), weight (lbs), and smoking (yes/no). How would you interpret the coefficients ...
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1answer
62 views

GEE iteration process

What is a simple description of how the GEE algorithm works? How exactly does the GEE process come up with the final estimates of the parameters?
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19 views

Estimating Equations

Suppose we have three random variables $X_1,X_2$ and $X_3$. Let $\bar{X}_{1:1:1}$, $\bar{X}_{1:1}$ and $\bar{X}_{2:1:1}$ be estimators for $\mu$. Note that the notation $\bar{X}_{1:1:1}$ indicates ...