Defining ESSA Levels of Evidence: An Overview

ESSA (Section 8002) and the U.S. Department of Education's Non-Regulatory Guidance: Using Evidence to Strengthen Education Investments outline four levels of evidence. The Non-Regulatory Guidance recommends that, "Organizations should select project components that are supported by the most rigorous evidence available, consider the needs of the learner population being served, and consider the ability and capacity of the organization to implement."

Level 1


Definition: Strong evidence from at least one well-designed and well-implemented experimental study.

What Does it Mean?

  • Experimental studies have demonstrated that the strategy improves a relevant student outcome (e.g., reading scores; attendance rates). Experimental studies (e.g., Random Control Trials) are those in which students are randomly assigned to treatment or control groups, allowing researchers to speak with confidence about the likelihood that a strategy causes an outcome.
  • Well-designed and well-implemented experimental studies meet the What Works Clearinghouse (WWC) evidence standards without reservations.
  • The research studies use large, multi-site samples.
  • No other experimental or quasi-experimental research shows that the strategy negatively affects the outcome.
  • Researchers have found that the strategy improves outcomes for the specific student subgroups that the district or school intends to support with the strategy.

Level 2


Definition: Moderate evidence from at least one well-designed and well-implemented quasi-experimental study.

What Does it Mean?

  • Quasi-experimental studies have found that the strategy improves a relevant student outcome (e.g., reading scores, attendance rates). Quasi-experimental studies (e.g., Regression Discontinuity Design) are those in which students have not been randomly assigned to treatment or control groups, but researchers are using statistical matching methods that allow them to speak with confidence about the likelihood that a strategy causes an outcome.
  • Well-designed and well-implemented quasi-experimental studies meet the What Works Clearinghouse (WWC) evidence standards with reservations.
  • The research studies use large, multi-site samples.
  • No other experimental or quasi-experimental research shows that the strategy negatively affects the outcome.
  • Researchers have found that the strategy improves outcomes for the specific student subgroups that the district or school intends to support with the strategy.

Level 3


Definition: Promising evidence from at least one well-designed and well-implemented correlational study.

What Does it Mean?

  • Correlational studies (e.g., studies that can show a relationship between the strategy and outcome but cannot show causation) have found that the strategy likely improves a relevant student outcome (e.g., reading scores, attendance rates).
  • The studies do not have to be based on large, multi-site samples.
  • No other experimental or quasi-experimental research shows that the strategy negatively affects the outcome.
  • A strategy that would otherwise be considered Level 1 or Level 2, except that it does not meet the sample size requirements, is considered Level 3.

Level 4


Definition: Demonstrates a rationale based on high-quality research findings or positive evaluation that such activity, strategy or intervention is likely to improve student outcomes or other relevant outcomes.

What Does it Mean?

The strategy cannot yet be defined as a Level 1, Level 2 or Level 3. This may be because the strategy has not yet been evaluated. It may be because the strategy has been evaluated, but the evaluations were not carried out with the methodologies associated with Level 1, 2 or 3. Or it may mean that the strategy has been evaluated, but not for the specific subgroups that you need to support.

Based on the research that does exist, there is good reason to believe that the strategy could improve a relevant student outcome.

Before using a Level 4 strategy, you should:

  • Explore Existing Research: Why do we believe this strategy will meet our needs?
  • Develop a Logic Model: How will the strategy improve student outcomes?
  • Plan to Evaluate: How will we know that the strategy is improving student outcomes?

Learn more about using Level 4 evidence-based strategies.