Benjamin Bloom, a researcher at the University of Chicago, conducted a landmark study in 1984 that showed students who received 1-on-1 tutoring performed two standard deviations better than students in group instruction. This has become known as the '2 Sigma Problem' in education research — the challenge of delivering that level of personalised effectiveness at scale. Online tutoring is the closest we have come to solving it.
The Core Problem with Group Classes
Group classes are designed for the average student. In a class of 25, the teacher necessarily pitches explanations at a level that the median student can follow. This means the top 25% of students are bored, the bottom 25% are lost, and only the middle 50% are genuinely benefiting at any given moment. In STEM subjects particularly, where each concept builds on the last, the students who are lost never catch up — and the gap widens over time.
Online group tutoring improves on school classes by having smaller group sizes (often 4–8 students), but the fundamental problem remains: the session cannot be personalised to your specific questions, your specific misconceptions, or your specific pace.
What Makes 1-on-1 Tutoring Effective
Immediate Feedback
In a 1-on-1 session, every question you attempt receives immediate feedback. If you make an error, the tutor identifies it in real time and addresses the underlying misconception before it is reinforced. In a group class, errors often go unnoticed or are corrected only at the end of the week when homework is marked — by which time the student has repeated the same mistake many times.
Adaptive Pacing
A skilled 1-on-1 tutor constantly adjusts the pace of teaching based on your understanding. If you master a concept quickly, they move forward. If you are struggling with a specific idea, they approach it from multiple angles — a diagram, an analogy, a worked example, a counterexample — until the concept clicks. This is impossible in a group setting.
Safe Space to Ask Questions
Many students are reluctant to ask questions in class because they fear judgement from peers. This is particularly damaging in Physics and Mathematics, where confusion builds cumulatively. In a 1-on-1 session, there is no social cost to asking a basic question — students ask more, understand more, and progress faster.
The Specific Benefits for STEM Subjects
Physics, Mathematics, and Chemistry are especially well-suited to 1-on-1 tutoring for three reasons. First, they are hierarchical — if you misunderstand Newton's second law, you will struggle with momentum, which means you will struggle with collisions, which means you will struggle with orbital mechanics. A tutor who identifies the foundational gap early can prevent this cascade.
Second, STEM problem-solving involves procedural steps that are easy to do incorrectly in subtle ways that are hard to self-diagnose. A tutor watching you work through a problem can immediately identify where your process goes wrong — something a textbook or video simply cannot do.
Third, STEM exams reward specific communication of reasoning — particularly at IB, A-Level, and AP levels. A tutor can teach you the exact language that examiners reward, which is difficult to acquire from self-study alone.
Online vs In-Person 1-on-1 Tutoring
Online 1-on-1 tutoring has, since 2020, been proven to be as effective as in-person tutoring for most students. The advantages of online tutoring include: access to tutors regardless of location, session recordings for later review, the use of digital whiteboards and screen sharing, and flexibility of scheduling. For students in remote areas or those who want access to the best tutors in the world, online tutoring has been transformative.
Finding the Right Tutor
- •Look for subject-specific expertise, not just general 'maths and science' qualifications.
- •Choose a tutor who has experience with your specific curriculum (IB, IGCSE, A-Level, CBSE, AP).
- •Book a trial session before committing to a long series — the tutor-student relationship matters enormously.
- •Ensure the tutor has a structured approach, not just 'do homework together' sessions.
- •Check reviews and ratings from students who have achieved specific grade improvements.
"The right tutor doesn't just teach you physics — they teach you how to think. That skill stays with you long after the exam."
— Ashish Pachar, PhyFix Founder