There was a more than five-fold increase in the number of vouchers used at two schools in Jefferson County this school year than last. With a voucher, or choice scholarship, public money is used to pay tuition at non-public schools.

At Christian Academy of Madison, there are 49 vouchers this year compared with nine last year, and at Prince of Peace Schools, 34 are using the voucher program this year compared with six last year. Prince of Peace President Phil Kahn said 11 of the students using the voucher program are in first grade.

"We've had great success with the program," Kahn said.

The state implemented choice scholarships in 2011, approving more than 4,000 Indiana students to receive vouchers. The state doubled the number of vouchers available this year to 15,000, and approved more than 8,000.

The constitutionality of Indiana's school voucher program, the largest in the nation, is being challenged in court. The Indiana Supreme Court will hear arguments by both sides Nov. 21.

Marion Superior Court Judge Michael Keele ruled Jan. 13 that Indiana's School Choice Scholarship program does not violate the state constitution because the state isn't directly funding parochial schools. Instead, it gives scholarship vouchers to parents, who can choose where to use them.

Opponents led by the Indiana State Teachers Association claim the program violates a state constitutional ban on government support of churches because it compels taxpayers to pay for schools that teach religion. They also argue in court briefs that because the schools teach religion, taxpayers are paying for religious instruction.

The Indiana attorney general's office and other groups defending the law argue that nobody is being compelled because parents are free to send their children to any school they want - public, private or parochial. They argue in briefs that striking down the program because some schools are affiliated with churches would amount to unnecessary government interference into religion.

To meet the requirements for the voucher, students must meet household income guidelines and have attended at least two semesters of public school not counting kindergarten.

At Prince of Peace and Christian Academy, several first-graders this year were eligible for the voucher program because last year they applied for a scholarship through the Scholarship Granting Organization, a program that is funded by donations from businesses and individuals. If students used the Scholarship Granting Organization program in kindergarten, they were eligible to begin the voucher program in first grade.

The deadline to apply for the school choice scholarship was Sept. 7.

Kahn said admissions are not based on how a student's tuition is paid.

The increase in voucher students is part of overall growth at Christian Academy of Madison. Administrator Anna Gosman said the school's enrollment increased to 135 students this year, compared with 110 last year. Part of the increase in enrollment this year came because the school added an 11th-grade class, she said.

• The Associated Press contributed to this story.