SGPC {glmtoolbox}

SGPC for Generalized Estimating Equations

Description

Computes the Schwarz-type penalized Gaussian pseudo-likelihood criterion (SGPC) for one or more objects of the class glmgee.

Usage

SGPC(..., verbose = TRUE, digits = max(3, getOption("digits") - 2))

Arguments

...

one or several objects of the class glmgee.

verbose

an (optional) logical switch indicating if should the report of results be printed. As default, verbose is set to TRUE.

digits

an (optional) integer indicating the number of digits to print. As default, digits is set to max(3, getOption("digits") - 2).

Value

A data.frame with the values of the gaussian pseudo-likelihood, the number of parameters in the linear predictor plus the number of parameters in the correlation matrix, and the value of SGPC for each glmgee object in the input.

References

Carey V.J., Wang Y.-G. (2011) Working covariance model selection for generalized estimating equations. Statistics in Medicine 30:3117-3124.

Zhu X., Zhu Z. (2013) Comparison of Criteria to Select Working Correlation Matrix in Generalized Estimating Equations. Chinese Journal of Applied Probability and Statistics 29:515-530.

Fu L., Hao Y., Wang Y.-G. (2018) Working correlation structure selection in generalized estimating equations. Computational Statistics 33:983-996.

Vanegas L.H., Rondon L.M., Paula G.A. (2023) Generalized Estimating Equations using the new R package glmtoolbox. The R Journal 15:105-133.

See Also

QIC, CIC, RJC, GHYC, AGPC

Examples

###### Example 1: Effect of ozone-enriched atmosphere on growth of sitka spruces
data(spruces)
mod1 <- size ~ poly(days,4) + treat
fit1 <- glmgee(mod1, id=tree, family=Gamma(log), data=spruces)
fit2 <- update(fit1, corstr="AR-M-dependent")
fit3 <- update(fit1, corstr="Stationary-M-dependent(2)")
fit4 <- update(fit1, corstr="Exchangeable")
SGPC(fit1, fit2, fit3, fit4)

###### Example 2: Treatment for severe postnatal depression
data(depression)
mod2 <- depressd ~ visit + group
fit1 <- glmgee(mod2, id=subj, family=binomial(logit), data=depression)
fit2 <- update(fit1, corstr="AR-M-dependent")
fit3 <- update(fit1, corstr="Stationary-M-dependent(2)")
fit4 <- update(fit1, corstr="Exchangeable")
SGPC(fit1, fit2, fit3, fit4)

###### Example 3: Treatment for severe postnatal depression (2)
mod3 <- dep ~ visit*group
fit1 <- glmgee(mod3, id=subj, family=gaussian(identity), data=depression)
fit2 <- update(fit1, corstr="AR-M-dependent")
fit3 <- update(fit1, corstr="Exchangeable")
SGPC(fit1, fit2, fit3)