Key points:
- Education has long struggled to help all students achieve concept mastery
- With advances in AI, computer-based tutors could be one of the solutions educators have long sought
- See related article: How AI learning is changing higher education
Benjamin Bloom explained the 2 sigma problem in his seminal 1984 article of the same title. Briefly stated, the problem consists of the following:
- The average student who is taught by a tutor using mastery learning techniques outperforms 98 percent of students taught in a typical classroom.
- Society cannot afford to provide full-time tutors for every student.
- As a result, the majority of students fail to reach their potential due to the way we teach them.
Because there appeared to be no viable path to providing each student with their own personal tutor, Bloom called on educational researchers to “find methods of group instruction as effective as one-on-one tutoring.” Educational technologists weren’t so quick to give up on the idea of providing every student with their own individual tutor, however, and have made laudable progress toward the 2 sigma goal by designing what are called intelligent tutoring systems (ITS). Unfortunately, these systems are both difficult and expensive to design and build, and typically work only in a single domain of knowledge (such as algebra).
The recent development of large language models (LLMs) like ChatGPT has opened entirely new possibilities for the design and implementation of computer-based tutors with the potential to help all students achieve Bloom’s two sigma performance threshold.
Dr. David Wiley is co-founder and chief academic officer of Lumen Learning, a company dedicated to increasing student success, reinvigorating pedagogy, and improving the affordability of education using a combination of open educational resources, learning analytics, continuous improvement, and professional development.
- Schools are building AI rules before they know the destination - August 17, 2026
- Cohort connections matter: Strategies to help graduate students persist and succeed - August 14, 2026
- Higher education needs better AI experiences, not more AI tools - August 12, 2026