In a 1984 paper that is regarded as a classic of educational psychology, Benjamin Bloom, a professor at the University of Chicago, showed that being tutored is the most effective way to learn, vastly superior to being taught in a classroom. The experiments headed by Bloom randomly assigned fourth-, fifth- and eighth-grade students to classes of about 30 pupils per teacher, or to one-on-one tutoring. Children tutored individually performed two standard deviations better than children who received conventional classroom instruction — a huge difference.
Affluent American parents have since come to see the disparity Bloom identified as a golden opportunity, and tutoring has ballooned into a $5 billion industry. Among middle- and high-school students enrolled in New York City’s elite schools, tutoring is a common practice, and the most sought-after tutors can charge as much as $400 an hour.
But what of the pupils who could most benefit from tutoring — poor, urban, minority? Bloom had hoped that traditional teaching could eventually be made as effective as tutoring. But Heffernan was doubtful. He knew firsthand what it was like to grapple with the challenges of the classroom. After graduating from Amherst College, he joined Teach for America and was placed in an inner-city middle school in Baltimore. Some of his classes had as many as 40 students, all of them performing well below grade level. Discipline was a constant problem. Heffernan claims he set a school record for the number of students sent to the principal’s office. “I could barely control the class, let alone help each student,” Heffernan told me. “I wasn’t ever going to make a dent in this country’s educational problems by teaching just a few classes of students at a time.”
How Computerized Tutors Are Learning to Teach Humans – NYTimes.com.