I've been utterly unable to locate studies which overtly question whether Children's Services is doing any good at all . However, a good mind and critical eye can secure valid data from even biased sources. This site contains a number of clinical expose's of Children's Services with plenty of stats and quotes. A great repository for worthwhile national data, mostly in .PDF format. Cornell has done everyone a good favor with its National Data Archive.
Site also contains some good web links.
This guy is over the top with his name-calling and cynicism. Read his work anyway. His research is brilliant. If you want to know about perverse funding incentives for Children's Services, this is THE place to go. Excellent clinical expose of Children's Services practices, complete with plenty of quotes, citations, and statistics.