vis_concurvity: Visualise concurvity between terms in a GAM

In dill/mgcvUtils: Some extra utilities for generalized additive modelling

Visualise concurvity between terms in a GAM

Description

Plot measures of how much one term in the model could be explained by another. When values are high, one should consider re-running variable selection with one of the offending variables removed to check for stability in term selection.

Usage

vis_concurvity(model, type = "estimate")

Arguments

model	fitted model
type	concurvity measure to plot, see concurvity

Details

These methods are considered somewhat experimental at this time. Consult concurvity for more information on how concurvity measures are calculated.

Author(s)

David L Miller

Examples

# example from ?concurvity
library(mgcv)
## simulate data with concurvity...
set.seed(8);n<- 200
f2 <- function(x) 0.2 * x^11 * (10 * (1 - x))^6 + 10 *
            (10 * x)^3 * (1 - x)^10
t <- sort(runif(n)) ## first covariate
## make covariate x a smooth function of t + noise...
x <- f2(t) + rnorm(n)*3
## simulate response dependent on t and x...
y <- sin(4*pi*t) + exp(x/20) + rnorm(n)*.3

## fit model...
b <- gam(y ~ s(t,k=15) + s(x,k=15),method="REML")

## assess concurvity between each term and `rest of model'...
vis_concurvity(b)

dill/mgcvUtils documentation built on Oct. 14, 2024, 7:30 p.m.