Chancellor Joel Klein is expanding a pilot program that takes the experiments city schools often conduct behind closed classroom doors and brings them to other schools.

Called Innovation Zone, or iZone, the program began this year in ten schools and will grow to include 81 schools next year. At its core is a heavy emphasis on expanding online learning, a major focus of Klein’s tenure at the Department of Education.

Of the iZone schools, more than half will adopt the “virtual school” model. This involves using online Advanced Placement classes and credit recovery courses or simply combining online work and face-to-face instruction. Six schools will alter their schedules to make the school day or year longer and 35 will begin using software that’s designed to change instruction based on how much a student struggles or excels.

One of the six schools that will change its schedule next year is P.S. 50, an elementary and junior high school in East Harlem. A spokeswoman for The After School Corporation said the organization is in talks with P.S. 50 to extend the school day to 6 p.m.

Many of the ideas for iZone schools’ alterations came from public schools like Brooklyn Technical High School, which designed its own online courses, and the Brooklyn Generation School, which radically changed its schedule to create an 11-month school year.

“We know each of these innovations has significant research demonstrating its potential to accelerate student learning,” White said. “Those that have the most impact, we’ll work to scale throughout the system.”

A Brooklyn high school, Victory Collegiate, is going to adopt elements of the Brooklyn Generation School’s schedule, which staggers teachers’ vacations to lengthen the school year and front-loads the school day with core subjects, giving teachers afternoon time to prep.

Next fall, ten schools will begin offering online credit recovery courses. Some, such as Curtis High School, are big schools with students who fail and have to retake courses for innumerable reasons. Others like Chelsea Career and Technical High School are small, but have a proportionally high number of students who are held back because they don’t accumulate enough credits to graduate.

Arthur VanderVeen, who is tasked with overseeing the iZone for the DOE, said the current model of credit recovery isn’t working for many students. “If a student fails a course their options generally are to retake the course in summer school or after school, and usually without very effective results,” he said.

“Schools that use online credit recovery see it’s an alternative approach that’s very engaging. They’re [students] getting that individualized attention and that’s often the difference.”

Online credit recovery programs could also lend some credibility to the process of making up class work or completing extra assignments that sometimes inspires skepticism from critics who see the standards as being too lax.

“This is the kind of delivery system that lends itself to greater rigor, which is what credit recovery needs,” White said. “There are more controls around what a student is obligated to do.”

Twenty schools — many of them with too few high-achieving students to hire a teacher for Advanced Placement classes — will adopt online courses next year. Students at these schools will be able to discuss their work in chat rooms with students and teachers at other schools, VanderVeen said.

Two schools — I.S. 339 and I.S. 228 — are going to become pilots for the School of One program next year, which began as an after-school program in M.S. 131, a Chinatown middle school, last summer. School of One will become part of the day for all three schools next year. The program focuses on math instruction and creates a computer-generated “playlist” of lessons for students.

Nominated by their school support organizations, 110 schools applied to be part of the iZone, which is being funded in part through about $2 million in donations from Cisco Global Education and the Ford Foundation, $3.2 million in stimulus funds, and additional capital fund dollars. DOE officials would not disclose the project’s total cost.