From the ACSI website:
"The Association of Christian Schools International (ACSI) promotes the value and worthiness of accreditation and encourages each school and early education program to continuously pursue excellence. This pursuit matches the biblical directive of approving "things that are excellent" (Philippians 1:10, KJV). The "accredited" seal denotes a school that has met institutional standards of quality, and verifies a commitment to strategic improvement and on-going accountability. The process of accreditation involves three significant elements:
Intensive, institution-wide self-appraisal, analysis, and improvement planning
External consultation, review, validation, and insights from a visiting peer group
Ongoing accountability for improvement through annual reporting and renewal."
From the Middle States Association website:
"Accreditation is the affirmation that a school or other educational institution is providing the level of quality in its educational programs, services, activities, and/or resources expected by its community of stakeholders and endorsed by the education world. When the Commissions on Elementary and Secondary Schools (CESS) accredit a school, they certify that the school meets the prescribed standards of quality of the Middle States Association.
To become accredited, or have its accreditation renewed, by the Middle States Association, a school must demonstrate that it meets the appropriate Standards for Accreditation. Recognizing the unique characteristics of schools and other educational institutions, the Middle States Commissions on Elementary and Secondary Schools have adopted Standards for Accreditation appropriate for each type of member institution."