The facts have already been collected please see the book: "Goodbye Good Men: How Liberals Brought Corruption into the Catholic Church" By Mike S. Rose. The investigation is there for all to read.
Rose caught a fair amount of flak from some of the people he describes, who said they were unfairly characterized, but I tend to think he mostly got it right.
The good news is that his book is a few years old, and some of the worst stuff he describes has been cleaned up, AFAIK.
The Bishops could buy and read Michael Rose's books and save themselves (and the parishioners who pick up the tab) the big expense of a "study".
One reason why I no longer donate to any "Bishops' Appeals".