The Research Behind CLASS®

The CLASS® tool was first developed in 2008 at the University of Virginia’s Center for Advanced Study of Teaching and Learning (CASTL). Since then, it has been validated in more than 200 peer-reviewed studies.

Key findings include:

• Effective educator–child interactions lead to better cognitive, behavioral, and social outcomes.
• Many pre-K classrooms show low-to-moderate levels of these interactions — highlighting the need for improvement.
• Even small increases in CLASS scores are linked to meaningful gains in child outcomes.
• Professional development aligned to the CLASS framework can reliably improve teaching quality.

Research shows that classrooms with higher CLASS scores consistently lead to the following benefits:

• Greater student behavioral engagement. More effective interactions in preschool are associated with gains in social competence and fewer challenging behaviors.
• Stronger vocabulary and reading outcomes. More effective educator-child interactions are associated with higher scores in vocabulary and reading, key skills for children about to enter kindergarten.
• Increased math achievement. More effective interactions in preschool are associated with increased math outcomes on tests that measure counting, numeracy, comparisons, addition/subtraction, telling time, and other basic early math skills.

Want to learn more about the evidence supporting the CLASS tool and the impact of meaningful interactions? Check out our research.