In 1984 psychologist Benjamin Bloom found out that one-on-one learning made a student score by 2 std better than a normally educated student. This means that students taught in a one-on-one sessions were in the top 2% of their peers. This is also called Bloom’s 2 sigma problem after a challenge set by Bloom to make mass learning as efficient as one-on-one.
“the average tutored student was above 98% of the students in the control class”
Distilled actions that may cause the 2 sigma increase are shown in the table bellow:
Addopting any one of them make the student learn faster and be better than the normal course.
This has been discussed on HackerNews as well
[Salman Kahn] believed that the current accepted method of teaching - students attending lectures and sitting in classrooms getting knowledge from teachers, then later doing homework alone trying to apply it - needs to be inverted. Lectures, presentations, textbooks can all be online and automated. Teaching resources, limited as they are, are much better spent helping students specifically when they are stuck and need more personalized help