Bootstrap covariance for a fixed-effects CPB fit

The covariance of the covariate coefficients from the stored pairs/cluster bootstrap (se = "bootstrap" at fit time); NULL when no bootstrap was run.

Usage

# S3 method for class 'cpb_fe'
vcov(object, ...)

Arguments

object

A "cpb_fe" object.

...

Unused.

Value

A covariance matrix, or NULL.