Function to solve a Generalized Estimation Equation Model
Produces an object of class "gee" which is a Generalized Estimation
Equation fit of the data.
gee(formula, id,
data, subset, na.action,
R = NULL, b = NULL,
tol = 0.001, maxiter = 25,
family = gaussian, corstr = "independence",
Mv = 1, silent = TRUE, contrasts = NULL,
scale.fix = FALSE, scale.value = 1, v4.4compat = FALSE)formula |
a formula expression as for other regression models, of the form
|
id |
a vector which identifies the clusters. The length of |
data |
an optional data frame in which to interpret the variables occurring
in the |
subset |
expression saying which subset of the rows of the data should be used in the fit. This can be a logical vector (which is replicated to have length equal to the number of observations), or a numeric vector indicating which observation numbers are to be included, or a character vector of the row names to be included. All observations are included by default. |
na.action |
a function to filter missing data. For |
R |
a square matrix of dimension maximum cluster size containing the user
specified correlation. This is only appropriate if |
b |
an initial estimate for the parameters. |
tol |
the tolerance used in the fitting algorithm. |
maxiter |
the maximum number of iterations. |
family |
a |
corstr |
a character string specifying the correlation structure.
The following are permitted:
|
Mv |
When |
silent |
a logical variable controlling whether parameter estimates at each iteration are printed. |
contrasts |
a list giving contrasts for some or all of the factors appearing in the model formula. The elements of the list should have the same name as the variable and should be either a contrast matrix (specifically, any full-rank matrix with as many rows as there are levels in the factor), or else a function to compute such a matrix given the number of levels. |
scale.fix |
a logical variable; if true, the scale parameter is fixed at
the value of |
scale.value |
numeric variable giving the value to which the scale parameter
should be fixed; used only if |
v4.4compat |
logical variable requesting compatibility of correlation parameter estimates with previous versions; the current version revises to be more faithful to the Liang and Zeger (1986) proposals (compatible with the Groemping SAS macro, version 2.03) |
Though input data need not be sorted by the variable
named "id", the program
will interpret physically contiguous records possessing the
same value of id as members of the same cluster. Thus it
is possible to use the following vector as an id vector
to discriminate 4 clusters of size 4:
c(0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1).
An object of class "gee" representing the fit.
Offsets must be specified in the model formula, as in glm.
This is version 4.8 of this user documentation file, revised 98/01/27. The assistance of Dr B Ripley is gratefully acknowledged.
Liang, K.Y. and Zeger, S.L. (1986) Longitudinal data analysis using generalized linear models. Biometrika, 73 13–22.
Zeger, S.L. and Liang, K.Y. (1986) Longitudinal data analysis for discrete and continuous outcomes. Biometrics, 42 121–130.
data(warpbreaks)
## marginal analysis of random effects model for wool
summary(gee(breaks ~ tension, id=wool, data=warpbreaks, corstr="exchangeable"))
## test for serial correlation in blocks
summary(gee(breaks ~ tension, id=wool, data=warpbreaks, corstr="AR-M", Mv=1))
if(require(MASS)) {
data(OME)
## not fully appropriate link for these data.
(fm <- gee(cbind(Correct, Trials-Correct) ~ Loud + Age + OME, id = ID,
data = OME, family = binomial, corstr = "exchangeable"))
summary(fm)
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