Overcoming the 2-Sigma Challenge: Problems Faced and Solutions

Overcoming the 2-Sigma Challenge: Problems Faced and Solutions


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Learning is very subjective in nature.

Every child responds to various learning methods in different ways. For example, some identify well with a classroom-based approach, while some are more at ease with self-paced learning.

Scores of studies have been conducted till date to identify what tops the charts as a general solution for all students worldwide. And the results have been pretty overwhelming. Numerous concepts like flipped classroom, blended learning gamification and so on have emerged to suffice for the learning gaps being observed among students who aren’t receptive of the conventional classroom-based approach towards learning.

But before jumping to conclusions, it is important to locate what works and what doesn’t. In fact, a study dating back to as early as 1984 had already put this dilemma to an end.

The 2-Sigma Problem

Conducted by educational psychologist, Benjamin Bloom, this study confirmed that an average student who has been tutored one-to-one in mastery learning method performed 2 standard deviations (or, 2 sigma) better than a student who has been exposed to conventional learning method. In simpler words, a tutored student performed better than 98% of the students subject to a classroom-based education.

This is more commonly known as ‘Bloom’s 2-Sigma Problem‘.

The following graph explains the study well.

This study shed light on two distinct methods of learning:


  • One-to-one tutoring
  • Mastery learning

In other words, personalized learning paired with regular feedback has been found to be the most effective among students. The best thing about this type of learning was that it resonates well with every student. According to Bloom, “The tutoring process demonstrates that most of the students do have the potential to reach this high level of learning.

The following video explain Bloom’s 2-Sigma problem in details.


Problem Encountered in Solving the 2-Sigma Controversy

The only problem that this type of learning encountered was the impracticality. First of all, one-to-one education is expensive. And secondly, if every student was shifted from a classroom-based learning approach to tutored learning, wouldn’t the conventional education system crumble down like a house of cards? And let’s face it, replacing the entire traditional education system with one-on-one tutoring is not feasible.

But the good news is, the 2-sigma problem was identified in the year 1984 when the Internet was not very common at many places in the world. So obviously, one-to-one learning wasn’t a convenient option for most students.

The upcoming years had a better plan up the sleeves.

Solution to the 2-Sigma Problem

 Welcome to the twenty-first century. The rise of computers and the miracle of the Internet has made our lives easier and education more accessible. With technology advancing rapidly to meet the standards of living and learning, the solution to the 2-sigma problem became far more achievable than ever imagined.

This solution can be achieved in two distinct steps.


  • Addressing mastery learning
  • Promoting one-on-one mentoring

Let’s look at each of these in more detail.

Addressing Mastery Learning

The good thing about mastery learning is that it can be practised in a conventional classroom scenario with slightly modified rules to make room for this new concept. This kind of learning focuses on helping students master one concept before moving on to the next. It relies heavily on regular feedback. In other words, a certain concept is explained to the students until the entire class masters it.

According to Bloom’s studies, mastery learning has been found to be responsible for an average student to perform better than 84% of his counterparts in a traditional learning environment. This means mastery learning solely could produce a 1-sigma gain in the performance of students. Now that’s half the problem solved.

Promoting One-to-One Mentoring

Several online programs have mushroomed over the years that employ one-to-one mentoring. These are self-paced, convenient and remove the constraint of the classroom walls, turning the classroom global. This way, the choice of the mentors becomes wide and chances for locating the right one for every student increase.


Another predominant aspect of one-to-one mentoring is that it is self-paced, which means that the system adjusts its pace according to the requirement of the student taking it. This means students can go as fast as they like or as slow as it suits them best, to fully grasp the concept before moving on to the next.

With a one-to-one mentoring in action, tutors create a study plan for the students which provides a concrete infrastructure for mentees to rely on.

When students are tutored individually, the lessons turn out to be more fruitful. Students are more engaged in the learning process and are no longer self-conscious about what their peers would think. It also removes any distraction that the tutor might overlook while teaching a group of students.

This promotes a healthy learning atmosphere that every student responds to.

The Problem Persists

 Even with all the shining benefits, online mentoring has received its fair share of challenges over the years. In a study conducted in the year 2013, it was found that the completion rate of Massive Open Online Courses (MOOCs) is less than 7%.

This turned out to be a backup for Bloom’s study results that confirmed that one-to-one mastery learning requires a classroom with both, student and tutor physically present, to be effective.

Even though this may not be completely achievable, it doesn’t mean that the idea cannot be executed with the resources that we have. There are ways to work around the feasible aspects and build a well-oiled system that is beneficial for all students.


Learnpick is an online marketplace for all kinds of tutoring and learning services. We provide a platform to help learners find home tutors, online tutors, expert trainers,tutorial centers, training institutes and online tutoring schools. Learners can also find local classes, workshops, online courses and tutorials on a huge variety of topics.

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