pseudoR2.SSN2 {SSN2}

Compute a pseudo r-squared

Description

Compute a pseudo r-squared for a fitted model object.

Usage

## S3 method for class 'ssn_lm'
pseudoR2(object, adjust = FALSE, ...)

## S3 method for class 'ssn_glm'
pseudoR2(object, adjust = FALSE, ...)

Arguments

object

A fitted model object from ssn_lm() or ssn_glm().

adjust

A logical indicating whether the pseudo r-squared should be adjusted to account for the number of explanatory variables. The default is FALSE.

...

Other arguments. Not used (needed for generic consistency).

Details

Several pseudo r-squared statistics exist for in the literature. We define this pseudo r-squared as one minus the ratio of the deviance of a full model relative to the deviance of a null (intercept only) model. This pseudo r-squared can be viewed as a generalization of the classical r-squared definition seen as one minus the ratio of error sums of squares from the full model relative to the error sums of squares from the null model. If adjusted, the adjustment is analogous to the the classical r-squared adjustment.

Value

The pseudo r-squared as a numeric vector.

Examples

# Copy the mf04p .ssn data to a local directory and read it into R
# When modeling with your .ssn object, you will load it using the relevant
# path to the .ssn data on your machine
copy_lsn_to_temp()
temp_path <- paste0(tempdir(), "/MiddleFork04.ssn")
mf04p <- ssn_import(temp_path, overwrite = TRUE)

ssn_mod <- ssn_lm(
  formula = Summer_mn ~ ELEV_DEM,
  ssn.object = mf04p,
  tailup_type = "exponential",
  additive = "afvArea"
)
pseudoR2(ssn_mod)