logistf (version 1.23.1)

add1.logistf: Add or Drop All Possible Single Terms to/from a logistf Model

Description

Compute all the single terms in the scope argument that can be added to or dropped from the model, fit those models and compute a table of the changes in fit.

Usage

# S3 method for logistf
add1(object, scope, test = "PLR", ...)
# S3 method for logistf
drop1(object, scope, test = "PLR", ...)

Arguments

object

a fitted logistf object

scope

The scope of variables considered for adding or dropping. Should be a vector of variable names. Can be left missing; the method will then use all variables in the object`s data slot which are not identified as the response variable.

test

The type of test statistic. Currently, only the PLR test (penalized likelihood ratio test) is allowed for logistf fits.

…

further arguments passed to or from other methods.

Value

A matrix with nvar rows and 3 columns (Chisquared, degrees of freedom, p-value).

Details

drop1 and add1 generate a table where for each variable the penalized likelihood ratio chi-squared, the degrees of freedom, and the p-value for dropping/adding this variable are given.

Examples

# NOT RUN {
data(sex2)
fit<-logistf(data=sex2, case~1, pl=FALSE)
add1(fit)

fit2<-logistf(data=sex2, case~age+oc+dia+vic+vicl+vis)
drop1(fit2)
# }