To qualify for a reduced-price lunch in public school, a family of four cannot earn more than $43,568, which is 185 percent of the federal poverty level. But a family of four can make up to $50,752 to be eligible for the statewide voucher program, and up to $70,947 for the Milwaukee or Racine choice programs.

Most public school students, 94 percent, who are considered economically disadvantaged qualify for the free lunch program, which means they have a family-of-four income of $30,615 or below, Johnson said.

It’s unclear how many students in the voucher schools could qualify for free and reduced-price lunches because the schools aren’t required to report that figure, Johnson said.

Matt Kussow of the Wisconsin Council of Religious and Independent Schools said the most accurate achievement comparison would include test results from all students in a private school, not just those receiving vouchers.

“Unless it includes the test results of every student in the private school, it will not be a true reflection of their success nor a real comparison with the public and charter schools,” Kussow said.

The statewide voucher program has about 500 students, according to DPI. The program’s enrollment limit will rise to 1,000 next school year.