wgeesel (version 1.5)

QIC.gee: QIC and QICu for GEE

Description

Calculate quasi-likelihood under the independence model criterion (QIC) and QIC\(_{u}\) based on GEE.

Usage

QIC.gee(object)

Arguments

object

a fitted model object of class "wgee".

Value

Return a vector of QIC, QIC\(_{u}\) and Quasi-likelihood.

References

Liang, K.Y. and Zeger, S.L., 1986. Longitudinal data analysis using generalized linear models. Biometrika, pp.13-22.

Pan, W., 2001. Akaike's information criterion in generalized estimating equations. Biometrics, 57(1), pp.120-125.

Prentice, R.L. and Zhao, L.P., 1991. Estimating equations for parameters in means and covariances of multivariate discrete and continuous responses. Biometrics, pp.825-839.

See Also

geeglm (geepack). MuMIn also provides QIC value.

Examples

# NOT RUN {
data(imps)
fit <- wgee(Y ~ Drug+Sex+Time, data=imps, id=imps$ID, family="binomial",
            corstr="exchangeable")

QIC.gee(fit)

data(seizure)
###reshapre the seizure data to "long" format
seiz.long <- reshape(seizure, varying=list(c("base","y1", "y2", "y3", "y4")),
                      v.names="y", times=0:4, direction="long")
seiz.long <- seiz.long[order(seiz.long$id, seiz.long$time),]

fit <- wgee(y ~ age + trt + time, data=seiz.long, id=seiz.long$id, 
            family="poisson", corstr="independence")

QIC.gee(fit)
# }