Compute the variance inflation factors (VIFs) for covariates in one level of the
model (i.e., occupancy or detection). Calculation of VIFs follows the approach
of function vif
in package car
, using the correlation matrix of
fitted model parameters.
vif(mod, type)
A named vector of variance inflation factor values for each covariate.
An unmarked fit object.
Level of the model for which to calculate VIFs (for example,
'state'
)