termPredictors {gnm}

Extract Term Contributions to Predictor

Description

termPredictors is a generic function which extracts the contribution of each term to the predictor from a fitted model object.

Usage

termPredictors(object, ...)

Arguments

object

a fitted model object.

...

additional arguments for method functions.

Details

The default method assumes that the predictor is linear and calculates the contribution of each term from the model matrix and fitted coefficients. A method is also available for gnm objects.

Value

A matrix with the additive components of the predictor in labelled columns.

Author(s)

Heather Turner

See Also

gnm

Examples

## Linear model
G <- gl(4, 6)
x <- 1:24
y <- rnorm(24, 0, 1)
lmGx <- lm(y ~ G + x)
contrib <- termPredictors(lmGx)
contrib
all.equal(as.numeric(rowSums(contrib)), as.numeric(lmGx$fitted)) #TRUE

## Generalized linear model
y <- cbind(rbinom(24, 10, 0.5), rep(10, 24))
glmGx <- glm(y ~ G + x, family = binomial)
contrib <- termPredictors(glmGx)
contrib
all.equal(as.numeric(rowSums(contrib)),
          as.numeric(glmGx$linear.predictors)) #TRUE

## Generalized nonlinear model
A <- gl(4, 6)
B <- gl(6, 1, 24)
y <- cbind(rbinom(24, 10, 0.5), rep(10, 24))
set.seed(1)
gnmAB <- gnm(y ~ A + B + Mult(A, B), family = binomial)
contrib <- termPredictors(gnmAB)
contrib
all.equal(as.numeric(rowSums(contrib)),
          as.numeric(gnmAB$predictors)) #TRUE