Description Usage Arguments Details Value Author(s) References See Also
gee
performs estimation of parameters in a restricted mean
model using standard GEEs with independent working correlation matrix. For
clustered data, cluster-robust standard errors are calculated. When
cond=TRUE
, cluster-specific
intercepts are assumed.
1 2 |
formula |
An expression or formula representing the expected outcome conditional on covariates. |
link |
A character string naming the link function to use. Has to be
|
data |
A data frame or environment containing the variables appearing in
|
subset |
An optional vector defining a subset of the data to be used. |
cond |
A logical value indicating whether cluster-specific intercepts should
be assumed. Requires a |
clusterid |
A cluster-defining variable or a character string naming a
cluster-defining variable in the |
clusterid.vcov |
A cluster-defining variable or a character string naming a
cluster-defining variable in the |
rootFinder |
A function to solve a system of non linear equations. Default
is |
... |
Further arguments to be passed to the function |
Estimates parameters in a regression model, defined by
formula
. When cond=FALSE
, the estimated coefficients are
identical to those obtained with glm
, but since no
distributional assumptions are made, a robust variance is
calculated. When cond=TRUE
and link
is "identity"
or "log"
, the coefficients will be calculated
using conditional estimating equations as described in Goetgeluk and
Vansteelandt (2008). When cond=TRUE
and link="logit"
,
the coefficients will be calculated by conditional logistic regression
(with robust standard errors).
gee
return an object of class gee
containing:
coefficients |
Estimates of the parameters. |
vcov |
Robust variance of the estimates. |
call |
The matched call. |
y |
The outcome vector. |
x |
The design matrix. For conditional methods there is no column corresponding to the intercept. |
optim.object |
An estimation object returned from the function specified
in the |
res |
The residuals from the estimating equations. |
d.res |
The derivative of the residuals from the estimating equations. |
data |
The original data object, if given as an input argument |
formula |
The original formula object, if given as an input argument |
The class methods coef
and vcov
can be used to extract
the estimated parameters and their covariance matrix from a
gee
object. To obtain the 'naive' variance, i.e. the variance
obtained from maximum likelihood estimation assuming correct
parameteric model and no clustering, use the class method
naiveVcov
. The class method summary.drgee
produces a
summary of the calculations.
Johan Zetterqvist, Arvid Sjölander
Goetgeluk S., & Vansteelandt S. (2008), Conditional generalized estimating equations for the analysis of clustered and longitudinal data. Biometrics, 64(3), pp. 772–780.
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