1. N

    Whats the best statistical analytical method to use

    Hi, I have a data set which has a treatment variable and some outcome variables which are the result of the treatments on certain markers measured daily. I would like to see if different levels of the treatment resulted in the differences in the outcome variable (there are 4 of these, each...
  2. C

    Reporting GEE results

    I'm working on a paper, and was struggling with how to analyze one question, and finally figured out that I needed to use GEE, ran the model, and thought I had done the hard part. But now I can't find any resources on how I'm supposed to report my GEE results in an APA paper. Any advice...
  3. C

    Defining Contrast Matrix

    In the book Applied Longitudinal Analysis, 2nd Edition there is an example in the chapter "Marginal Models: Generalized Estimating Equations (GEE)" in "Muscatine Coronary Risk Factor Study" sub-section. I am illustrating it below : Let Y_{ij}=1if the i^{\text{th}} child is classified as obese...
  4. C

    Hypothesis difficulty

    Let Y_{ij}=1 if the i^{\text{th}} child is classified as obese at the j^{\text{th}} occasion, and Y_{ij}=0 otherwise. The marginal probability of obesity at each occasion follows the logistic model log\frac{\Pr(Y_{ij}=1)}{\Pr(Y_{ij}=0)}=...
  5. P

    Adjusting for clustered observations

    Hello, I have collected mortality data and several covariates (data on treatment and vital parameters) from patients in two different hospitals. My goal is to analyse effects of treatments on mortality while adjusting for covariates, and using logistic regression would be my first choice to...
  6. B

    Power analysis for GEE

    I am designing a study that would require using GEE (generalized estimating equations) to analyze repeated measures of a dichotomous variable. Is there a way to estimate the sample size required for this analysis? Thank you!
  7. P

    Generalized Estimating Equations (GEE): full factorial or separate interactions?

    Hello everyone, I have a question regarding full-factorial design and separate interactions using Generalized Estimating Equations (GEE). My research is about spatial biases and choice between the left and right sides. By using GEE separate interactions results show that bias is to the left...
  8. R

    Using Generalized Estimated Equations (GEE) to analyze correlations?

    I have repeated measures data (meaning 3 measures per type of animal for one treatment only; there are 2 types in total) that are unbalanced. There are 2 treatments. Additionally, these animal 'types' are nested within group, which are nested within a cage. Now, because of the difficulty of...
  9. R

    Data analysis with a GEE, is my method valid?

    Hi everyone, 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 kind of at the limit of my understanding, so I was hoping that I could run through...
  10. P

    Exchangeable or Unstructured GEE

    Hi all, I was wondering if someone can give me a clear understanding on the difference between exchangeable working correlation matrix and unstructured working correlation matrix and when is best to use one or the other? Many thanks!
  11. A

    Goodness of fit (QIC) in Generalized Estimating Equations (GEE)

    Hi, I have a question concerning goodness of fit which is measured as QIC in the GEE analysis: In general I learned that if QIC decreases the change in the model was for the better. => Decrease in QIC = Good However, I am trying to add new model terms and for all of them QIC...
  12. A

    How to apply GEE and how to use it for critical mass

    Hi, sorry I am completely new to the forum and as well to using GEE and SPSS so I hope my question is not to confusing. My dependent variable is the firm performance and I have several controlling variables. First of all I am not sure how to set up my independent variable. I would like to...
  13. H

    How do I perform a generalized estimate equation with penalized maximum likelihood... SPSS? The reason I ask is that SPSS tell me I have a quasi-complete separation of my data and after some reading I have found that using penalized maximum likelihood could help me solve this problem. Is there other ways (maybe simpler) that could help me solve the problem?
  14. H

    Choice of test in R. Repeated measurements, binary response and missing data...

    I have two treatments and one co-variate (affect the response variable but is also correlated with one of the treatments). Each replicate has been examined for the presence/absence of morphological characters at several time point but there are unfortunately a lot of missing data. What would be...
  15. P

    Which statistical test? GEE?

    Hello! I'm currently playing which my data and am unsure about the statistical test to use. I have MRI data from 25 patients. I have 4 (predetermined) lesion types and a control area from which I obtained MRI values. Not all patients have all lesion types, some patients have several of the...
  16. M

    GEEGLM for longitudinal data in the sport sciences

    I have measured power output in a small group (n=7) of elite athletes before and after training as an indicator of neuromuscular fatigue. This was repeated on many sessions (n=6) over the course of a training block. I am particularly interested in assessing the change in power output from...
  17. B

    How to analyze data with more than one associated categorical dependent variables?

    I have some dependent variables related to the growth of a company having categories like (e.g. for variables indicating net profit, financial turnover etc.) (1) decreasing, (2) stable, (3) increasing and (4) rapidly increasing. Now these variables are associated and ordinal in...
  18. B

    Regression with some associated ordinal dependent variables

    I have some associated categorical dependent variables that are ordinal in nature (with 4 or 5 categories). If I want to see the effect of a set of independent variables (which can be both continuous and categorical) what is the right way to perform the regression? Should that be a...
  19. D

    Using Generalized Estimating Equations to test item validity on a scale

    Hi, I am creating a new measurement scale for withdrawal from cannabis, and have daily withdrawal data from 50 people for 1 week before abstinence (baseline smoking as usual) and then for 2 weeks of abstinence. There are 26 items on this new scale, and essentially what I want to is to rank...