QIC: QIC for Generalized Estimating Equations

Description

Computes the quasi-likelihood under the independence model criterion (QIC) for one or more objects of the class glmgee.

Usage

QIC(
  ...,
  k = 2,
  u = FALSE,
  verbose = TRUE,
  digits = max(3, getOption("digits") - 2)
)

Value

A data.frame with the values of -2*quasi-likelihood, the number of parameters in the linear predictor, and the value of QIC (or QICu if u=TRUE) for each glmgee object in the input.

Arguments

...: one or several objects of the class glmgee.
k: an (optional) non-negative value giving the magnitude of the penalty. As default, k is set to 2.
u: an (optional) logical switch indicating if QIC should be replaced by QICu. As default, u is set to FALSE.
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).

References

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

Hin L.-Y., Carey V.J., Wang Y.-G. (2007) Criteria for Working–Correlation–Structure Selection in GEE: Assessment via Simulation. The American Statistician 61:360–364.

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.

Examples

Run this code

###### 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")
QIC(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")
QIC(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")
QIC(fit1, fit2, fit3)