Statisticians who study education talk in terms of effect sizes, or standardized units. In education research, effect sizes of 0.2, or two tenths of a standardized unit (in response to a treatment), attract considerable attention. Many prominent professors report effect sizes of 0.1 or even 0.05. The early childhood interventions that President Obama touted had an effect size of about 0.3. Anything more than 0.5, in education, is rare.
Benjamin Bloom, the legendary education professor and creator of Bloom’s Taxonomy, found an educational intervention with an effect size of 2.0. The difference between this intervention and other educational interventions is the same as the difference between the atomic bomb and conventional explosives. The intervention?
One-on-one tutoring.
In the early 1980s, in a series of randomly controlled trials in a variety of high school courses, he found that students who received one-on-one tutoring performed two standard deviations better than students in a classroom course. In other words, the average student in the tutoring program was better than approximately 98% of the students in the classroom course. Delving deeper, 90% of the students in the tutoring program were in the top 20% of the students in the control classroom course.
This result is not surprising if you take a broad and deep look at education. In the fitness world, personal trainers have never been more demanded. Life coaches, corporate mentors, executive coaches and related fields have multiplied. Some theorize that holistic medicine practitioners have prospered because they spend much more time, one-on-one, with their patients than traditional doctors. SAT preparation instructors, quality free material on the web notwithstanding, have never commanded higher prices.
Deeper, one-on-one education is the history of education. The master-apprentice model has endured for thousands of years. Most royalty throughout history were tutored. (Interestingly, many of their tutors were famous philosophers, like Aristotle tutoring Alexander the Great, and Rene Descartes tutoring the Queen of Sweden.)
Bloom called his finding the two sigma “problem” because he thought one-on-one instruction would be too expensive to implement on a wide scale; he was issuing a challenge to researchers to find ways of teaching that were as effective as one-on-one instruction.
Sadly, he did not try to polish his silver bullet. Although his tutors were not completely green, being trained in “mastery learning” techniques, the question is forced: What kind of effect would truly awesome tutors, who are widespread throughout the private sector, have?
A Stanford psychologist, Mark Lepper, tried answering this question a few years later. He was prompted by the large increase in computer-based tutoring systems. He found the literature on the subject lacking (it still is, by the way) and conducted his own original research.
He found that some tutors were extraordinary, way outperforming other tutors and getting results from otherwise intransigent students. Their methods were ancient: essentially, the Socratic method. (He found that 80% of the sentences uttered by the best tutors during a session were questions.)
He goes into great detail about the tutors, the extraordinary tutors, and the methods. It can be summarized in a sentence: extraordinary tutors were experts, used the Socratic method, and kept their students continuously engaged (using a variety of strategies) for the duration of a session.
An object of the study, almost 20 years old now, was to provide a framework for designers of educational software. The goal was to get the impact of tutoring without the cost. And although the technology has gotten exponentially more powerful, it still has not been able to replicate the power of one-on-one instruction.
A goal of this blog will be to explore and explain why one-on-one instruction – from tutoring, to coaching, to counseling, to mentoring – is so unreasonably and irreplaceably effective.