The single question presented by this appeal is whether, under the Individuals with Disabilities Education Act (“IDEA”), 20 U.S.C. § 1400 et seq., a school board is legally obligated to provide a sign language inter*395preter to a disabled student voluntarily enrolled in private school. The district court found that the IDEA required the school board to provide the on-site interpreter, and the school board appeals. We vacate the decision of the district court and remand this case for further consideration in the light of our opinion.
I
Charles Tony Cefalu, III (“Cefalu”) has suffered from a hearing impairment since birth. Cefalu attended public schools until the conclusion of the 1992-93 school year. Cefalu’s individualized education program (“IEP”), prepared in accordance with the requirements of the IDEA, included the services of a sign language interpreter.
In June 1993, the Supreme Court held that a public school district did not violate the Establishment Clause by providing services under the IDEA to students voluntarily attending parochial schools. Zobrest v. Catalina Foothills Sch. Dist., 509 U.S. 1, 113 S.Ct. 2462, 125 L.Ed.2d 1 (1993). Thereafter, Cefalu’s parents withdrew their consent from a previously devised IEP, which included a sign language interpreter at a public school, and enrolled Cefalu at Redemptorist High School, a private school. The Cefalus then requested that a sign language interpreter be provided at Redemptorist. The school board refused the Cefalus’ request and again offered a sign language interpreter at the public school. The Cefalus refused to consent and requested an IDEA due process hearing. See 20 U.S.C. § 1415(b)(2).
In October 1993, the administrative hearing officer ruled that the school board was not obligated to provide Cefalu with an interpreter while at Redemptorist, because the offer to provide an interpreter at the public school provided Cefalu with an opportunity for a free appropriate public education. The decision of the hearing officer was affirmed on appeal to the state level review commission. See 20 U.S.C. § 1415(c). Cefalu then sought review in federal court. See 20 U.S.C. § 1415(e)(2).
The federal district court heard cross-motions for summary judgment. Based upon the record, consisting of the administrative record and a joint stipulation, the court granted Cefalu’s motion and ordered the school board to provide a sign language interpreter at Redemptorist. The court denied the board’s motion to stay the judgment pending appeal. The board did not seek a stay from this court.
II
A
We review the district court’s grant of summary judgment de novo, using the standard utilized by the district court. See, e.g., Brock v. Chater, 84 F.3d 726, 727 (5th Cir.1996). In conducting judicial review of an IDEA administrative decision, the court “shall receive the records of the administrative proceedings, shall hear additional evidence at the request of a party, and, basing its decision on the preponderance of the evidence, shall grant such relief as the court determines is appropriate.” 20 U.S.C. § 1415(e)(2).
B
(1)
This appeal requires us to interpret the IDEA and its regulations. The IDEA provides federal grants to states, which in turn provide funds to local school districts to establish special education and related services for children with disabilities. States that accept the funds are required to adopt a policy and a plan that “assures all children with disabilities the right to a free appropriate public education.” 20 U.S.C. § 1412. The IDEA defines a “free appropriate public education” to include
Special education and related services that—
(A) have been provided at public expense, under public supervision and direction, and without charge,
(B) meet the standards of the State educational agency,
(C) include an appropriate preschool, elementary, or secondary school education in the State involved, and
*396(D) are provided in conformity with the individualized education program required under section 1414(a)(5) of this title.
20 U.S.C. § 1401(a)(18). “The word ‘public’ is a term of art which refers to ‘public expense,’ whether at public or private schools.” Dreher v. Amphitheater Unified Sch. Dist., 22 F.3d 228, 233 n. 10 (9th Cir.1994) (citing Florence County Sch. Dist. Four v. Carter, 510 U.S. 7, 12-14, 114 S.Ct. 361, 365, 126 L.Ed.2d 284 (1993)).
Local school districts receiving funds under the IDEA are required to prepare an IEP for each disabled student, whether in public or private school. The IEP must identify the special education and related services that are necessary to meet that student’s needs, and the district must offer to provide those services at public expense. 20 U.S.C. §§ 1412(4), 1414(a)(1), 1414(a)(5). If the district is unable to provide the necessary services to the disabled student, then the student must be placed in a private school that can address the student’s needs at public expense. 20 U.S.C. § 1413(a)(4)(B). These mandatory private school students are distinguished under the IDEA and its regulations from students, such as Cefalu, who voluntarily are enrolled in private schools.
Students voluntarily attending private schools are addressed by the provision requiring each state’s plan to set forth policies and procedures to assure—
(A) that, to the extent consistent with the number and location of children with disabilities in the State who are enrolled in private elementary and secondary schools, provision is made for the participation of such children in the program assisted or carried out under this subchapter by providing for such children special education and related services.
20 U.S.C. § 1413(a)(4)(A). The school district is not required to pay a student’s private school tuition if he is voluntarily enrolled in private school; however, the district “shall make services available to the child as provided” by other regulations enacted pursuant to the IDEA. 34 C.F.R. § 300.403.
The other regulations referenced above require each local educational agency to “provide special education and related services designed to meet the needs of private school children with disabilities residing in the jurisdiction of the agency.” 34 C.F.R. § 300.452. Additionally, local agencies are to ensure that, “[t]o the extent consistent with their number and location in the State, provision is made for the participation of private school children with disabilities in the program assisted or carried out under this part by providing them with special education and related services.” 34 C.F.R. § 300.451(a). Local education agencies are also charged with “providing] students enrolled in private schools with a genuine opportunity for equitable participation” and “provid[ing] that opportunity to participate in a manner that is consistent with the number of eligible private school students and their needs.” 34 C.F.R. § 76.651(a)(1) & (2). The local agency is required to consult with private school students’ representatives regarding which students will receive benefits, how the students’ needs will be identified, what benefits will be provided, and how benefits will be provided. 34 C.F.R. § 76.652(a). Local educational agencies are to determine the needs of private school students, the number of private school students to be participants in a project, and the benefits that the agency will provide to those students using a “basis comparable to that used ... in providing for participation of public school students.” 34 C.F.R. § 76.653. Finally, “[t]he program benefits that [an agency] provides for students enrolled in private schools must be comparable in quality, scope, and opportunity for participation to the program benefits that the [agency] provides for students enrolled in public schools.” 34 C.F.R. § 76.654(a).
It is clear, therefore, that the IDEA differentiates among three categories of disabled students: (1) those attending public schools; (2) those placed in private schools by local school districts; and (3) those attending private schools voluntarily. With respect to public school students, the IDEA requires that all children with disabilities receive a free appropriate public education that covers the expense of special education and related services. 20 U.S.C. §§ 1412(1), 1412(2)(B), *3971412(4), 1414(a)(5). Students placed in private schools by local school districts are to receive the same benefits as those attending public schools. 20 U.S.C. § 1413(a)(4)(B). The regulations require that students voluntarily attending private schools be provided with an “equitable opportunity for participation” in the program “to the extent consistent with the number and location” of such students. 34 C.F.R. § 76.651(a)(1) & (2). Today, we are required to address the application of the IDEA only as it relates to this third category of disabled students.
(2)
When an attempt is made to apply the foregoing statutory provisions and regulations to specific cases involving disabled students voluntarily attending private school, we see that the IDEA and its implementing regulations are amorphous in design and imprecise in message. By necessity, therefore, the statute and regulations must be regarded as affording considerable discretion to educational agencies because their terms are to be applied in sundry factual situations. Such flexibility for local officials, however, comes with attendant costs. The IDEA and the corresponding regulations seldom provide a road map to local educational agencies regarding the extent of their obligations under the Act and the manner in which those obligations must be fulfilled, thus leaving a considerable area open to dispute.
In attempting to glean the essence of the statute and regulations, however, certain points are salient as they relate to the question before us. First, and fundamental, the drafters of the IDEA plainly intended that-students voluntarily enrolled in private schools be active participants in and beneficiaries of the program. See 20 U.S.C. § 1413(a)(4)(A) (West 1990). Such students are entitled to “a genuine opportunity for equitable participation” in programs and services provided under the IDEA. 34 C.F.R. § 76.651. It is clear that the statute does not mandate that services for students voluntarily enrolled at private schools be provided on-site at the private school. However, the refusal to provide services on-site implicates the student’s right to “equitable participation.”
It is implicit in the statute and the regulations that educational agencies must be afforded the broadest discretion to design special programs in the light of the finite funds that are available. The regulations support the proposition that these limited resources must be distributed in a manner that allows the provision of necessary services to the greatest number of qualified students within in the relevant district, when all other appropriate criteria in the decision-making process have been considered. The regulations address this concern by stating that the average amount spent per pupil should not vary according to whether the student attends public or private school but, instead, should vary only according to the cost required to fulfill the special education needs of the student. 34 C.F.R. § 76.655. It is in this context that the obligation of the agency arises to “set forth policies and procedures to assure that, to the extent consistent with the number and location of handicapped children in the State who are enrolled in private elementary and secondary schools, provision is made for the participation of such children in the program assisted or carried out under this subchapter by providing for such children special education and related services.” 20 U.S.C.A. § 1413(a)(4)(A) (West 1990) (emphasis added). This provision, which is also reflected in the regulations, allows the educational agency to exercise discretion in determining the manner in which services are to be provided to disabled children in public and private schools. This discretion is to be exercised in a way that assures the private school student a “genuine opportunity for equitable participation” in the program, but, that also considers the “number of eligible private school students and their needs.” 34 C.F.R. § 76.651. The word “equitable,” certainly in the context of the finite funds available, means fair to all concerned, not simply fair to the private school student; in this context, it means not unfair to others depending on the same pool of money for services and benefits.
Thus, we arrive at our second point that is plain from the Act and regulations: *398although private school students are eligible to receive benefits under the program, they are not entitled to a greater share of benefits, nor of the funds providing those benefits, per student, than similarly-situated students in public schools.
The statute and regulations, therefore, lead to the following rule to apply in disputed cases in the posture of the one before us: The private school student must make an initial showing of a genuine need for on-site services, based upon more than mere convenience. Upon such showing, the agency must provide on-site services unless it presents a justifiable reason, either economic or non-economic, for its denial of on-site services. The student then bears the burden of showing that the agency’s position is inconsistent with the IDEA and its regulations, or is not rationally supportable, or is otherwise arbitrary.
The general application of this rule will ensure that educational agencies fulfill their obligation to provide private school students with a “genuine opportunity for equitable participation” in IDEA services. Under this general approach, private school students usually will, absent justifiable non-economic considerations, be provided comparable services on-site to the extent that such services can be provided on-site at the same approximate cost as that incurred in providing the services at other sites.1 See Russman v. Sobol, 85 F.3d 1050, 1056-57 (2d Cir.1996). The rule will also ensure that disproportionately large sums of scarce money are not required to be spent to benefit a reduced number of students.
Ill
Finally, we come to the question whether the school board here is obligated to provide Cefalu an interpreter on-site at Redemptorist. In this connection, there is no evidence in the record that indicates the basis of the school board’s decision. Absent such evidence, we are unable to determine whether the denial of services under the IDEA was appropriate.2 For that reason, we VACATE the judgment of the district court and REMAND for further consideration and action *399in the light of this opinion.3
VACATED and REMANDED.
. The Seventh Circuit in K.R. v. Anderson Community Sch. Corp., 81 F.3d 673 (7th Cir.1996), held that educational agencies had broad discretion in determining what services to provide to students enrolled in private schools. K.R., 81 F.3d at 679. We agree that the agency has broad discretion in determining what services to provide generally; in other words, the agency has broad discretion in formulating an IEP for a student. The IDEA and the regulations grant discretion to the educational agency to determine what services to provide to an individual student, but, once that decision is made, and the student has made a showing of genuine need for on-site • services, those services should be provided on-site at the private school, absent justification as noted above. If such justification is demonstrated, nothing in our opinion should be construed as precluding the agency and the affected parties from voluntarily negotiating a solution to their dispute that may result in services less than comparable to the services provided to a public school student.
. The dissent charges that we are deciding more than is at issue in this appeal, pointing out that the stipulated issue is whether the school board is legally obligated to provide the subject service to Cefalu. With due respect, our view of the case is that we cannot answer this question because we do not know the basis upon which the school board made its decision. The dissent acknowledges that the school board’s discretion to deny on-site services to private school students is limited. There is nothing in the record to tell us whether the school board exceeded that limit; therefore, we conclude that this case must be remanded for further development on this point.
Neither do we understand how the dissent concludes that our interpretation of the IDEA and its regulations is inconsistent with the interpretation of the United States Department of Education. There is nothing in this opinion that suggests that the local agency is automatically required to pay for Cefalu's education at Redemptorist. Our opinion emphasizes, as do the regulations, that the private school student is entitled to a genuine opportunity for equitable participation and that the agency must "provide that opportunity to participate in a manner that is consistent with the number of eligible private school students and their needs." There is nothing in our opinion that holds that an individual private school student is automatically entitled to receive on-site services comparable to those that he would receive at a public school. Furthermore, there is nothing in this opinion that can be read to favor the private school setting over the public school setting when only one service can be provided. Thus, we respectfully differ with the dissent’s position that this opinion somehow conflicts with the interpretations promulgated by the Department of Education.
. For the first time in its reply brief, the State Department of Education requests that the Cefalus be required to reimburse it for the costs of the interpreter that the district court ordered it to provide during the pendency of this appeal. As noted, the appellants did not seek a stay pending appeal. In any event, we do not address the issue because it was first raised in a reply brief.