The Flipped Classroom and Bloom's Two Sigma
The Flipped Classroom and Bloom’s Two Sigma
Flipped classroom
Content at home (video, reading, simulation); activity, discussion, and practice in class the next day.
Role shift
Sage on the stage becomes coach on the side: the teacher corrects, sets practice, and helps students learn from mistakes.
Start small
A gentle first step into technology. The teacher is always still needed.
Bloom’s Two Sigma
Benjamin Bloom (1984): one-to-one tutored students scored about two standard deviations higher than class-taught peers. Technology is proposed as a scalable way toward that gain.
Schools rarely swap to full technology teaching overnight, and they do not need to. The flipped classroom is a gentle first step: it keeps the teacher central while moving some learning onto devices. Understanding it also explains why a decades-old study, Bloom’s Two Sigma problem, keeps coming up whenever people argue for technology in the classroom.
What a Flipped Classroom Is
A flipped classroom reverses the usual order. The technology work happens at home: a student watches an animation, reads the material, or runs a simulation the night before. Class time the next day is then free for the activity, the discussion, the case study, or the puzzle that shows whether the learning actually stuck. The lecture moves out of the room, and the practice moves in.
Many teachers find this an easy way to begin, because they can see they are still needed. Starting small with a flipped model, a teacher may over time move further toward fully technology-enabled lessons. No matter how far it goes, the teacher stays part of the room.
That reversal changes what the teacher does during class time.
Content is studied at home; practice and discussion happen in class.
Students watch a video, read, or run a simulation before class. Class time is then used for activities and discussion that check and deepen the learning, reversing the usual lecture-then-homework order.
From Sage on the Stage to Coach on the Side
When the lesson is learned at home, the teacher is no longer the “sage on the stage,” the one holding all the facts. The next day the teacher works as a coach on the side. A coach corrects mistakes, sets learners to practise, and helps them learn from what went wrong. That is different from a common classroom habit: spotting a mistake, marking the student down, and stopping there. Marking an error is not the same as fixing it. Learning happens when students practise the right thing until they can do it.
Making this shift work in a real class takes trial and error, which is the next hurdle.
Experiment, Reflect, Adjust
No single model fits every room. A tool that works for one teacher may fall flat for another, because teachers differ and so do their beliefs about how children learn. So early on, expect a lot of experimenting to find what fits a particular class. The easy response when something fails is to give up and return to the old routine. A better one is to reflect: was the tool understood, were students prepared, were the materials and equipment ready? Analyse why it did not work, fix that, and try again.
The reason this effort is worth making comes from a study that still shapes the whole debate.
Bloom’s Two Sigma Problem
In 1984 the educational psychologist Benjamin Bloom reported that students given one-to-one tutoring performed far better than those taught in a conventional class: about two standard deviations higher, which put the average tutored student above roughly 98 percent of the class-taught group. This finding is known as Bloom’s Two Sigma problem. It is widely cited as evidence that one-to-one attention lifts performance.
The trouble is scale. A normal school cannot give every child a private tutor; it is not a luxury but a practical impossibility. This is where technology enters the argument. If the software becomes the patient, one-to-one “tutor” while the human teacher acts as coach, then a room of forty students could each get personalised attention at once. Technology is proposed as a scalable way toward the Two Sigma gain, though it remains a proposal to work toward, not a guaranteed outcome.
The promise, then, is not that a device equals a human tutor. It is that well-chosen technology could bring one-to-one attention within reach of an ordinary class, which no timetable could otherwise afford.
One-to-one tutored students scored about two standard deviations above class-taught peers.
That gain (roughly the 98th percentile) is hard to scale, since schools cannot tutor every child privately. Technology is proposed as a scalable route toward that personalised attention.
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