R the default contrasts used for ordered factors is Polynomial contrasts. However, this link says:
This type of coding system should be used only with an ordinal variable in which the levels are equally spaced.
In real life, we often have ordered factors, such as income low medium high, education, high school, bachelor, master, phd. BUT these levels almost never equally spaced.
Is it wrong for
R to use Polynomial contrasts as default coding for ordered factors?