To help close its $629 million budget shortfall, the Philadelphia School District plans to close 13 schools for students on the verge of dropping out and cut funding for remedial disciplinary programs in half.

Operators who have contracts with the district to run the popular "accelerated" programs, which help at-risk students and those who already have dropped out earn diplomas, said they were told of the changes this week.

Those who run disciplinary schools also were told of cuts to their programs.

Shana Kemp, a district spokeswoman, said the 50 percent cut to alternative education was announced previously, although providers learned details this week. She said the changes would save $25 million.

These cutbacks come as the district considers eliminating full-day kindergarten, slashing transportation, and curtailing art and music programs to balance a proposed $2.7 billion budget for 2011-12.

Kemp said the district planned to close the 13 accelerated schools, which have a total enrollment of about 1,800 students, and replace them with programs in district high schools.

Proponents of the existing options said the plans were shortsighted, would prove costly in the long run, and would undermine the city's efforts to improve high school and college graduation rates to boost the local economy.

"As previous president of Congreso de Latinos Unidos, who served and advocated for Philadelphia's young people in one of Philadelphia's most impoverished communities for the past 10 years, I tell you that this is a mistake," Nicholas Torres, cofounder of Social Innovations Journal, an online public-policy publication, said Friday.

He said the district's accelerated schools had become "the preferred and only option for young people who dropped out of school or are in the process to dropping out of school."

Torres pointed out that an independent evaluation of the district's accelerated high schools last year said they were successful and popular with students and parents.

He added, "I simply don't understand why we would cut programs that are working."

Todd Bock, president of Camelot Schools, a for-profit company that specializes in alternative education and operates three accelerated high schools in the city, agreed.

"I think there are other things to look at before it comes to that," he said. "Twenty-five million dollars, in the grand scheme of things, is a great investment in the long run."

Camelot's accelerated schools enroll 855 students and have a 95 percent graduation rate. Bock said that 386 students would graduate from Camelot this year, and that nearly all were headed to postsecondary education.

He said he was told the district planned to replace accelerated schools with 100-student programs inside 10 neighborhood high schools.

"We don't think this is a good idea at all," he said. "These kids are the most at-risk kids in the district."

He said the district had asked Camelot to consider providing the instruction at some schools at a rate of $3,000 per student. That's about half what Camelot receives for the longer hours it requires to help students catch up.

Camelot, which also operates disciplinary schools, will receive nearly $17 million from the district this academic year.

Kemp said alternative education providers were told months ago that "major changes would be coming in the operation of these programs."

As a result of those changes, the district expects to be able to serve 500 more students, Kemp said. "The district is well prepared to educate all students while maintaining the same level of service at a lower price," she said.

She said that the cuts to the district's 19 disciplinary schools, or "transition" programs, for students who have been suspended from their schools would save $6 million. Students in the programs receive services for 90 days or more, then return to their original schools. Kemp said about 2,000 students were in the programs.

Camelot runs two transition schools, enrolling 833 students, some of whom are middle schoolers. Bock said officials told him that the district planned to make the programs half-day instead of the full-day programs offered now. Providers would be asked to serve the same number of students but split them into four-hour shifts: half in the morning, half in the afternoon.

Bock said he feared that half-day shifts would mean the district's most dangerous students would spend more time on the streets.

Kemp, however, said that Ben Wright, the district's head of alternative education, had said transition programs for disciplinary students would remain full-day.