The California Society of CPAs has a superb article on the Peer Review program in their October 2016 newsletter: Be Prepared – A Comprehensive Peer Review Update.
Here is the link again: http://californiacpa.calcpa.org/?issueID=65&pageID=15
I will check to see if I can get permission to reprint the article.
Update: CalCPA graciously gave me permission to reprint the article. You may find it here.