What high school your son attends is one of the most important decisions you’ll make as a parent. Today, families are concerned with affordability. However, when you understand the benefits of a Catholic school, you’ll come to the conclusion that money, although important, should not be your first concern. Catholic schools hold students accountable to high standards of behavior and performance. Parents should look for a school that works in partnership - a “shared mission”- with the family, something that Catholic schools are committed to doing.
For further reading, please see… http://www.csoadmin.org/whychoose.htm
Please also see what Brother Patrick Sean Moffett, CFC, Ph.D had to say (PDF).