A principal reason districts cite increasing staffing ratios—whether by adding teacher aides, instituting team teaching, or lowering class size—is the challenge of “differentiating instruction” to meet the needs of an educationally heterogeneous population in each class. But a far more effective—and less costly—solution is to change how classes are formed.
While much attention has been given to the size of classes, almost none has been directed to how they are formed. Classes are not chance aggregations of pupils; at least in principle, they are composed of students who have mastered the prerequisite skills and knowledge to function in the class. But in most American schools students are assigned to classes based on age—regardless of whether they have demonstrated such mastery. As students move up the grades, their teachers confront an increasingly unmanageable array of undiagnosed knowledge gaps among their students; these gaps impede the acquisition of new skills and explain the dismaying fall-off in student performance in the middle and high schools grades that is a hallmark of American schools. Exhorting teachers to address these gaps through “individual attention” or, to use the current buzzword, “differentiated instruction” is a fool’s errand.
The SABIS model of class formation proposes an alternative. The SABIS International Charter School in Springfield, Massachusetts enrolls 1,574 students in kindergarten through twelfth grade and has the largest waiting list, nearly 2,700 students, of any Massachusetts charter school. Tenth graders from low-income families outperform their peers in the Springfield district schools by 45 percentage points on the state’s respected MCAS test (92 percent proficient or advanced, compared to 46 percent) in English and 50 percentage points in Math (83 percent versus 33 percent proficient or advanced) and for the past seven years every SABIS Springfield high school graduate has been admitted to an institution of higher learning.39 The school has literally closed the achievement gap by race and income; tenth-graders in the low-income and African-American NCLB subgroups outperform the average student statewide. In 2008, Newsweek named the school just one of three urban “top U.S. high schools” in Massachusetts.40
Students are placed in grades by skills level, not age. From phonics in kindergarten through AP classes in high school, students are taught each learning objective to mastery. Through electronic assessment tightly keyed to the curriculum, their teachers are alerted immediately when they fail to demonstrate mastery of a skill they have just been taught. Rather than move forward, their teacher re-teaches the concept or arranges for tutoring of individual students by their peers so that knowledge gaps do not form that undermine later learning. A schoolteacher can no more successfully introduce algebra to students who have not mastered division than a college professor can teach an advanced chemistry class to students who have not completed basic courses in the subject.
So equipped, SABIS teachers routinely succeed with classes of thirty students. Ralph Bistany, SABIS’s founder, sees it is as SABIS’s mission to demonstrate that a world-class education can be delivered affordably and scoffs at those who claim thirty children cannot be taught effectively in one classroom. “First, we need to define the word ‘class,’” he says. “Every course has a prerequisite—concepts that the course is going to use but not explain. That list of concepts determines who belongs in the class and who doesn’t.” If the course is German, and one student is fluent and others cannot speak a word of the language, the students obviously should not be taught together, he explains. At SABIS, students in a class have the same background but neither, he hastens to say, “the same ability nor the same knowledge.” So formed, it doesn’t matter whether the class has ten students or fifty. “In fact, fifty is better,” he adds. “We have worked with classes of seventy in countries where it is allowed, and it has worked like a charm.”
The Efficient Use of Teachers by Steven F. Wilson Ascend Learning, Inc.
A Penny Saved: How Schools and Districts Can Tighten Their Belts While Serving Students Better
“fifty is better”