Here is some information about the IHSA process.
IHSA Assigning Process
In this link, there is some current information about what losing coaches and winning coaches rated officials. The percentage differences are only a few tenths of a percentage point. Coaches also have to answer a few questions before the ratings go through. They have to answer if a call affected their rating or opinion of the official. I think a copy of the ratings form is on this link.
Peace