There are certain circumstances where a Parent of a student with special needs may decide to place their child in a private placement even if they believe the school district is providing an appropriate placement.
A parentally-placed private school child with a disability is, under the law a child "with disabilities enrolled by their parents in private, including religous schools or facilities that meet the definition of elementary school or secondary school," who have not been referred to that placement by the LEA. See 34 CFR 300.130. When you have privately placed your student, generally speaking, you are not entitled to services for that student.
School districts do, however, have an obligation to allocate some special education funds to parentally-placed private school children. If the school district decides to provide a student with any services they must develop an individual services plan, which describes the specific special education and related services to be provided to each private school student. See 34 CFR 300.132(b). These service plans are to be developed, reviewed, and revised consistent with the procedures governing IEPs. See 34 CFR 300.137(c)(1). In preparing service plans and providing services, the district must consult with private school representatives. See 34 CFR 300.137(c)(2). In particular, the district must ensure that a representative of the private school attends these meetings, or in the alternative, uses other methods to secure the involvement of such individuals such as individual or conference phone calls.
IEPs are generally more comprehensive than the more limited services plans developed for parentally placed private school children with disabilities designated to receive services. A services plan should reflect only the services offered to a parentally placed private school child with a disability designated to receive services and must, to the extent appropriate, meet the IEP content requirements or, when appropriate, for children aged three through five, the IFSP requirements as to the services that are to be provided. See Questions and Answers on Serving Children with Disabilities Placed by Their Parents at Private Schools, 106 LRP 57733 (OSEP 2006).