The Complete Guide to CLASS

Everything you need to know about the CLASS tool, how it works, and how to do it.

What Is CLASS®?

CLASS is an acronym of Teachstone’s observation tool, the Classroom Assessment Scoring System®. It measures what matters most to children’s learning and development: interactions among educators and children. 

But CLASS is more than a measurement tool. It also provides a specific descriptions of impactful educator-child interactions, based on research. These descriptions are a shared language for educators to use as they improve their practice. With CLASS at the center of continuous improvement, educators can focus on the interactions that impact children most.

Programs and school districts across the country (and internationally!) use CLASS to help ensure all children in their programs have access to effective educator-child interactions. This system supports educators in focusing on, measuring, and improving the elements of classroom experience that matter most for supporting children’s learning and development.

So, how did CLASS come about? Our understanding of what classroom quality means has changed quite a bit over the past 25 years. It used to mean giving children a safe place to play, with plenty of stimulating materials and books to read.

Now that most classrooms provide these basics, education leaders have shifted their focus. This shift aligns with decades of research on what matters most for children. These leaders are asking: 

  • How can educators interact with children to best support learning? 
  • How can they use time and materials to get the most out of every moment? 
  • How can they ensure that children are engaged and stimulated? 
  • How can they ensure that every child has access to high-quality education?

Researchers designed CLASS to answer these questions. Over time, more and more programs started using this evidence-based system. Today, it is the most widely used tool for assessing classroom quality. 

In 2022, Teachstone announced CLASS 2nd Edition, which incorporates enhancements with a focus on improving equity, access and impact. These innovations, developed in partnership with the field, include more inclusive and diverse definitions and representation, considerations for scoring across diverse settings and guidance for reducing bias. In addition, the updates provide educators with actionable insights on the experiences and interactions that play an important role in child development.

What are CLASS Domains and Dimensions?

The CLASS tool is a structured observation measure. At its heart are trained and certified observers who assign scores. These scores are in different categories of educator-child interactions. The 7-point scale is a consistent approach to measuring these categories. Its metrics, for ages ranging from infants to teens, are developmentally appropriate.

We call these categories CLASS domains and dimensions. They give us a common definition of effective interactions across age/grade levels and content areas. The domains and dimensions vary somewhat across age groups, in line with how kids learn and develop as they grow.

Each age level contains domains that measure effective interactions. And under each domain are dimensions. This chart shows the age levels, domains, and dimensions of the CLASS tool.

Want to learn more about what interactions look like in each CLASS dimension? Read the CLASS Manual or undergo training to become a certified CLASS observer.

What Do CLASS Scores Mean?

Certified CLASS observers use the CLASS tool to capture the quality of the educator-child interactions they see in a classroom. These observers look for certain behavioral markers. They then assign scores across each dimension.

  • Low-range scores (1–2): the behaviors were lacking, rarely present, or of low quality
  • Mid-range scores (3–5): the behaviors were somewhat present or a part of just some children’s experience
  • High-range scores (6–7): the behaviors were consistently present and reflect every child’s experience

We recommend that observers share their findings with classroom educators. The program can determine the extent of this feedback. Some educators might get detailed scores, notes, and comments. Others might get only general feedback about what they did well and not so well.

Effective data collection and reporting are key. To support that, we offer the myTeachstone CLASS Subscription to move CLASS beyond measurement. With this subscription, programs can improve how they

  • Observe, collect data, and make notes.
  • Monitor quality and efforts to improve.
  • Share CLASS data with classroom educators
  • And more!

Feedback and data collection are important, but there is more that programs can do. An effective program also offers data-backed professional development and 1:1 coaching.

Who Uses CLASS?

Anyone can use CLASS! It can be at the center of a whole ecosystem of continuous quality improvement. Use CLASS in a classroom, a program, a district, a state, or at the federal level.

States and Systems

Used at scale, CLASS helps individual programs, districts, states, and even federal programs to improve child outcomes through the power of interactions. The system works with any curriculum and in any educational setting. These include family childcare homes, private centers, Head Start, and K–12 schools. system. Some institutions even use CLASS alongside another assessment system.

Interested in learning more about how CLASS has made a difference? Check out these case studies:

Program Leaders

Programs that use CLASS have a common language and the same expectations of educators. The result is a shared metric for evaluating how effective teachers are.

What CLASS does so well is to offer a common way to describe effective interactions. This creates consistency for children as they advance in the program or school. The tool also creates a culture where everyone focuses on the same goal: to provide more meaningful interactions for the children in their care. 

It is important for leaders to feel confident in implementing CLASS. As part of a successful rollout, program leaders should

  • Understand why interactions are the best predictors of child outcomes.
  • Create and share a vision of success for their program.
  • Support educators in the classroom.
  • Create an action plan to improve CLASS scores.
How to Implement CLASS in Your Program

Enroll in CLASS Primer for Leaders, a 2-hour online course that will walk you through how to effectively roll out CLASS.
Learn More

Talk to a CLASS Consultant, who can work with you to create an individualized plan that fits your goals and budget.
Connect with Us

Instructional Coaches

The key to continuous quality improvement is effective coaching. When that is in place, programs can drive the types of change that help kids develop and learn.

Coaching with CLASS is not about bumping scores from 5 to 6. Impactful coaches understand that the key to success is

  • Building relationships with educators
  • Understanding their goals and challenges
  • Working together as a team

Coaches can help educators achieve their goals by using the parallel processes found in the CLASS tool. 

Teachstone also provides coaching certifications and trainings that can build your capacity to support educators, no matter where they are in their CLASS journey.

CLASS Master Coaching

This comprehensive program supports coaches seeking to deepen their practice. Coaches engage in a parallel process based on the CLASS tool and work to improve the interactions they have with the educators they support.
Learn More

CLASS Group Coaching

This is a structured group coaching model. It immerses educators in CLASS professional development to improve teaching behavior. By creating an in-house CLASS coach, the program helps educators develop awareness and bring about change in the classroom.
Learn More

CLASS 1-1 Video Coaching

Build highly effective CLASS coaches to provide educators with an intensive, personalized experience. This practice-based program trains coaches to support educators using classroom videos that guide learning and self-reflection.
Learn More


Educators have little control over the size of their program or budget. But they can control classroom interactions.

To support educators’ understanding of the power of interactions, organizations may choose to use CLASS Primer for Educators. This 3-hour online course provides the foundational knowledge to energize staff around your CLASS implementation and journey. It offers digestible content designed to increase understanding of effective interactions,  reflect on current teaching practices, and learn about the CLASS tool, and your program’s CLASS implementation.

Teachstone has many free resources that help educators focus on interactions. Use them for different age groups, setting, and learning activities. We also invite you to subscribe to our Teaching with CLASS podcast in which you’ll hear specific tips and strategies for improving interactions in your classroom.

How CLASS Works

Quality education is good for everyone—kids, educators, communities—and is essential in building a national commitment to education. But just what is quality education? To learn how CLASS works and how it came to be, it is important to understand the research behind the tool.

In 2008, education researchers at the University of Virginia’s Center for Advanced Studies in Teaching and Learning (CASTL) published CLASS to capture the essence of great teaching in a scientific way. Since then, more than 200 research studies have validated this system.

Research Context

A study, conducted by the National Center for Early Development and Learning (NCEDL), examined the quality of publicly funded preschool programs. In this study, researchers created the first version of the CLASS observation tool from an adaptation of the Classroom Observation System (COS). They used this tool to measure teacher-student interactions in nearly 700 public preschool programs across 11 states. Just like the NICHD study, researchers observed the quality of classroom interactions and assessed the academic and social development of randomly selected children in those programs.

The findings from these and later studies prove the importance of educator-child interactions. Some highlights:

  • Effective educator-child interactions lead to better cognitive, behavioral, and social outcomes.
  • Many pre-K classrooms have low or moderate levels of interactions. This suggests that many children in early childhood programs are not consistently exposed to the types of interactions that lead to social and academic gains.
  • Small differences in educator-child interactions are associated with real differences in children’s outcomes.
  • Carefully designed and implemented professional-development supports can improve the quality of educator-child interactions. 

The research showed a need to continue focusing on interactions. And so, education researchers developed the Classroom Assessment Scoring System (CLASS) to better understand and measure the quality of those interactions.

Later research shows that quality interactions, as measured by the CLASS tool, lead to 

  • 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 also associated with increased math outcomes on tests that measure counting, numeracy, comparisons, addition/ subtraction, telling time, and other basic early math skills.

There have been many CLASS-based studies over the past decade.  One of the most important findings is that educators can improve their interactions with kids. But how? Researchers tested several professional development programs and found that they produced higher scores. The increases ranged from one-fifth to a full point on the 7-point CLASS scale. Even small increases add up to real improvements in quality and child outcomes.

Professional development includes coaching and coursework. An important resource is a video library of examples of effective teaching. These and other efforts are proven ways to raise CLASS scores.

Want to learn more about the studies behind CLASS and the impact of meaningful interactions? Check out our research.

How to Do CLASS?

focus measure improve graphic

Continuous quality improvement is a cyclical journey. To make real progress, you need to be intentional and systematic. CLASS is unique in two ways: 

  • It offers a framework and resources that align with a plan-do-study-act approach.
  • It empowers an ongoing journey toward improvement with flexible offerings that meet your needs.


When implementing CLASS, begin by building a foundation where meaningful interactions can thrive. Help your program understand why educator-child interactions are key. Do this by

  • Creating a clear vision
  • Preparing people for change
  • Establishing foundational knowledge of quality interactions
Learn More about Focus Products
We offer intro courses for leaders and teachers.

CLASS Primer for Leaders

We designed this online course with busy leaders in mind. It explains the power of CLASS, then offers advice for planning and leading CLASS implementation. This training is 2 hours / 0.2 CEUs.
Learn More

CLASS Primer for Teachers

This course covers the basics of CLASS and gets teachers excited about their upcoming journey. The digestible content talks about CLASS, the importance of interactions and the latest teaching practices. This training is 3 hours / 0.3 CEUs.
Learn More


Next up is to create a system that drives data-informed improvement. Quality interactions call for both attention and intention. That’s why CLASS-centered professional development shows results. Its definitions are a shared lens for understanding what effective teaching looks like. For this reason, CLASS lends itself well to continuing education and new teacher training.

CLASS data measures educator-child interactions in your program, and collecting this data will guide continuous improvement. Build your program’s capacity to observe interactions, collect reliable data, and use it to drive improvement at the classroom and program level.

Create your program’s plan to secure certified CLASS observers. We offer options to

Learn more about Measuring with CLASS, the second stage of a CLASS journey.

Learn More about Measure Products


Stage one was to lay the foundation. Stage two was collecting baseline data. The third step is to drive continuous improvement throughout your program. Use CLASS data to create tailored professional development and coaching opportunities that help educators improve their teaching practices. 

Take a close look at the data. Where are the areas of weakness? Which learning opportunities will best meet the needs of your educators and coaches?

For even better results, have one or more members of your staff become a CLASS coach. This training and certification program shows them how to

  • Coach effectively in CLASS.
  • Strengthen teaching abilities in the CLASS system.
  • Provide CLASS-based feedback that is specific and actionable

Encourage the educators in your program to

  • Get credentialed. 
  • Understand how to support interactions at different age levels.
  • Invest in meaningful relationships.
  • Create a learning environment that promotes quality interactions.

Check out myTeachstone. With 1,000+ resources, this online platform lets you do so many things:

  • Build coaching capacity to drive improvement.
  • Create unique opportunities for professional development.
  • Offer on-demand learning activities.
  • Generate CLASS data reports.
  • Engage the entire organization in shared learning.
Learn More about Improve Products

More about CLASS

Ready to learn even more about the CLASS tool and what it could mean for your program? Connect with a CLASS Consultant to get started on your journey today.