How Does CLASS® Work?

How Is the CLASS® Tool Organized?

The CLASS tool is a structured observation measure. It’s built on Teachstone’s Interaction Framework, which organizes the ways educators support children into three categories: to connect with them, to engage them, and to inspire their learning. To capture these interactions, the tool is organized into domains that reflect broad categories of educator–child interactions. Dimensions within each domain describe more specific aspects of those interactions.

The exact set of domains and dimensions can vary depending on the age level or edition of the CLASS tool. Still, every version is grounded in Teachstone’s Interaction Framework and focused on what matters most for children’s learning and development. Across all versions, the CLASS tool provides a consistent, research-based way to describe and understand effective educator–child interactions.

Below, you can see how the domains and dimensions are organized in the CLASS® 2nd Edition Infant–Toddler tool and the CLASS® 2nd Edition Pre-K–3rd tool.

What Happens During a CLASS® Observation?

CLASS observations are conducted by trained, certified observers. Certified CLASS observers visit learning settings and carefully watch the interactions that take place between educators and children, and among the children. Observers watch for several 15–20 minute observation periods, called cycles, to capture a well-rounded picture of what happens across the day. After each cycle, they assign a numerical score on a seven-point scale for each CLASS® dimension, based on the depth, frequency, and duration of the effective interactions they observed.

What Do CLASS® Scores Mean?

Certified CLASS observers use the CLASS tool to capture the quality of educator-child interactions in a classroom. Observers assign scores on a seven-point scale across each dimension.

Scores reflect the depth, frequency, and duration of effective interactions:

• Low-range scores (1–2): Interactions were rare, brief, or tended to stay at a surface level without meaningfully supporting children’s needs or learning.
• Mid-range scores (3–5): Interactions happened sometimes or for some short periods. Some interactions were effective and supportive, while others may have been brief or fleeting. Children experienced a mix of deeper and more surface-level moments.
• High-range scores (6–7): Interactions were consistently effective. They frequently met children’s needs or deepened children’s experiences, learning, and connections.

CLASS® scores provide program leaders with a clear and meaningful way to see what’s working well and where there are opportunities to strengthen everyday interactions. Leaders can make data-informed decisions to create impactful professional development opportunities with educators. To make the most use of CLASS data, we recommend that program leaders provide educators with an opportunity to discuss the results of their observations within two weeks of their observations. For more information on effective use of CLASS data, explore our CLASS Implementation Guide.

See how Dara, a pre-K educator, experienced a CLASS observation