In The Right Mix, Education Sector’s Susan Headden profiles a charter high school in Los Angeles that’s using blended learning to personalize instruction — despite having 48 students in a class. The Alliance Tennenbaum Family Technology High School “combines online and traditional instruction and allows students to learn in three different ways,” she writes.

On this particular fall day, 16 students are getting traditional in-person instruction in Algebra I from teacher Wendy Chaves; roughly the same number are doing math problems online; and still others are gathered in clusters of four tutoring each other. No matter where they are in the rotation, they see the student-to-teacher ratio as what it effectively is—an ideal 16-to-1.

Students work at their own pace, Headden writes. “With the software taking up chores like grading math quizzes and flagging bad grammar, teachers are freed to do what they do best—guide, engage, and inspire.”

Tennenbaum’s BLAST model breaks the day into two-hour blocks with students spending 40 minutes at each station.

Students report to stations based on what regular pre-tests have shown they can do. The low performers go right to direct instruction with the teacher, the high performers start with the collaborative session, and those in the middle start with online work.

Let’s say the English lesson is about effective use of literary devices. Students might start with a teacher-led lesson on metaphor, personification and the like, followed by an online tutorial on the MY Access! writing program. They write a short essay, which the computer immediately scores for mechanics and grammar. If the student has too many mistakes, he takes another tutorial and writes the essay again. He sets himself a deadline (say, all clean by the third draft), and when he has met it, submits the piece to the teacher for feedback on meatier qualities like content and orga­nization. Finally, in the collaborative session, students critique each other’s work, making suggestions for improvement based on what they have learned from the teacher and online.

Students don’t move ahead until they show mastery. Online programs let students review a lesson until they understand it. The software analyzes keystrokes to collect data on each student’s learning.

Tennenbaum has excellent teachers, but mediocre software, says Principal Michelle Tubbs.  “There is no A-plus software out there,” Tubbs says. “Most of it is C-plus or below.”

Technology lets the school hire fewer teachers, but the savings are wiped out by technology costs. However, once the school reaches full enrollment, the technology is expected to pay for itself.

“When computer-assisted learning fails, it is usually because technology has been deployed as an add-on,” writes Headden. “BLAST shows that for technology to make a difference in student learning, it must be integral to instruction, and it must come with humans attached.”

Public Impact’s new Opportunity Culture Charter School Network hopes to use technology to enable excellent teachers to reach more students. Four new schools plan different approaches to creating an “opportunity culture” for teachers: Foundations College Prep (Chicago), Ingenuity Prep (Washington, D.C.), Touchstone Education (Newark) and Venture Academy (Minneapolis).