R: Extract Term Contributions to Predictor

termPredictors {gnm} | R Documentation

## 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

[Package gnm version 1.0-8 Index]