The main function is drgee
, which estimates a parameter
beta in a model defined as
g{E(Y|A,L)}-g{E(Y|A=0,L)}=beta^T
(A * X(L))}. By supplying (nuisance) models for
g\{E(Y|A=0,L)
and E(A|L), a consistent estimate of beta is
obtained when at least one of these models is correctly specified.
In the function drgee
, three estimation methods are
implemented:
O-estimation, where a model for g\{E(Y|A=0,L) is used;
E-estimation, where a model for E(A|L) is used; and
DR-estimation where models for both g\{E(Y|A=0,L) and
E(A|L) are used.
The function gee
is an implementation of standard GEE with
independent working correlation matrix.
For conditional methods with clustered data, cluster-specific intercepts are assumed in all models.
The function drgeeData
is used for extraction and manipulation
of data, and is called by drgee
and gee
.
The function RobVcov
is used to calculate standard errors of
the estimates, given a vector of the residuals from estimating
equations, the Jacobian, and a cluster-identifying variable.
The function findRoots
solves a system of non linear equations.
Johan Zetterqvist, Arvid Sjölander with contributions from Alexander Ploner.
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