  My first paper exclusively about ridge regression was published in
Technometrics and chosen for invited presentation at the 1975 Joint Statistical
Meetings in Atlanta. Unfortunately, that paper contained a wide range of
assorted details and results. Luckily, Gary McDonald's published discussion of
that paper focused primarily on my use of Maximum Likelihood estimation under
normal distribution-theory. In this review of some results from all four of my
ridge publications between 1975 and 2022, I highlight the Maximum Likelihood
findings that appear to be most important in practical application of shrinkage
in regression.

Methodology