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 from the output of the GEE function seems to disagree with what I believe it should be given my data.
Here's a small example, where I have six observations from each of ten patients, which are members of one of three groups:
ID <- rep(1:10, 6) myData <- data.frame(ID) myData$ID <- factor(myData$ID) myData$Group <- c(rep('A', 20), rep('B', 20), rep('C', 20)) myData$value <- rnorm(60, mean = 10, sd = 1)
summary(myData$ID) shows that I do, in fact, have six observations of each ID, and calling
class(myData$ID) shows that
ID is, in fact, a factor. Therefore, I would expect that the maximum cluster size would be six. However, when I call the following...
gee(value ~ Group, id = ID, data = myData)
Maximum cluster size that prints out is
Am I misunderstanding what maximum cluster size means? Incorrectly formatting my data? Thanks in advance.