A method for extracting confidence intervals for parametric terms from an mgcv gamObject and returning a tidy data frame

confint.gam.R

confint.gam <- function(mod, level = 0.95) {
  # a method for extracting confidence intervals and returning a tidy data frame
  require(mgcv)
  require(dplyr)
  
  mod.s <- summary(mod)
  
  E <- data.frame(Estimate = mod.s$p.coeff) %>%
    mutate(Term = row.names(.)) %>%
    select(Term, Estimate)
  
  SE <- data.frame(SE = mod.s$se) %>%
    mutate(Term = row.names(.)) %>%
    select(Term, SE)
  
  nu <- mod.s$residual.df
  
  inner_join(E, SE) %>%
    mutate(L = Estimate +
             SE * qt(df = nu,
                     p = (1 - level) / 2),
           U = Estimate +
             SE * qt(df = nu,
                     p = 1 - (1 - level) / 2)) %>%
    return
  
}