Accreditation is achieved through a rigorous process of self study and documentation, in which a school frankly examines both its strengths and areas that need improvement. Because it's central purpose is to affirm that a school is what is says it is, and does what it says it does, the process invariably results in ongoing pedagogic improvement and professional development.
In fact the self-study process is one of discovery and empowerment. Each school's self study focuses on its philosophy and its constituents, resulting in strong self-evaluation and a strategic plan that fosters continuing school improvement.