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ESSA evidence refers to the four tiers of evidence defined in the Every Student Succeeds Act (Public Law 114-95): strong, moderate, promising, and demonstrates a rationale. Education grant applications use these tiers to show that a proposed activity, strategy or intervention is evidence-based. The sections below separate what the statute says from what U.S. Department of Education (ED) guidance, as summarized by a federal NCES program, adds. This page describes the law and guidance as stated on the cited pages on 2026-10-29.
What it is and who runs it
The Every Student Succeeds Act (ESSA) amended the Elementary and Secondary Education Act of 1965 (ESEA) and added a definition of “evidence-based” to section 8101. The statute sets the definition; ED issues non-regulatory guidance on how to apply it; and the Institute of Education Sciences’ What Works Clearinghouse (WWC) supplies the design standards that the guidance uses to separate the top two tiers. Because the tiers come from the statute, they are also called the ESSA tiers of evidence or the Every Student Succeeds Act evidence tiers.
What the four ESSA evidence tiers require
Under the statute, an activity, strategy or intervention is evidence-based if it meets one of two tests. Tiers 1 to 3 require that it demonstrates a statistically significant effect on improving student outcomes or other relevant outcomes, based on at least one well-designed and well-implemented study of a stated type. Tier 4 requires a research-based rationale plus ongoing evaluation.
| Tier | Statutory basis (at least one well-designed and well-implemented study) | Added by ED guidance, as summarized by REL Central |
|---|---|---|
| 1. Strong evidence | Experimental study | Meets WWC group design standards without reservations (a well-implemented randomized controlled trial with low attrition); large multisite sample; at least one statistically significant positive outcome |
| 2. Moderate evidence | Quasi-experimental study | Meets WWC group design standards with reservations (a randomized trial with high attrition, or a well-implemented quasi-experimental design with baseline equivalence met); large multisite sample; at least one statistically significant positive outcome |
| 3. Promising evidence | Correlational study with statistical controls for selection bias | Correlational design comparing treatment and comparison groups with statistical controls for selection bias; a statistically significant positive effect; does not meet WWC standards |
| 4. Demonstrates a rationale | A rationale based on high-quality research findings or positive evaluation that the activity is likely to improve outcomes, and ongoing efforts to examine its effects | A well-specified logic model with at least one intended outcome aligned to a stakeholder need, supported by existing or ongoing research on how the activity is likely to improve those outcomes |
The middle column is statutory text; the right column is guidance language. If a funder asks for a tier by name, the statute is the controlling definition and the guidance explains how ED reads it.
ESSA evidence tiers: where the statute and the guidance differ
The statute asks for “at least 1” well-designed and well-implemented study for tiers 1 to 3. The guidance summary adds a large multisite sample and maps tiers 1 and 2 onto WWC ratings. An applicant who consults only the statute can underestimate what a reviewer will look for in the strong and moderate tiers.
Eligibility: which programs may rely on which tiers
The tiers are not interchangeable across ESEA programs. Per the statute, for interventions and improvement activities funded under section 1003 (school improvement), “evidence-based” means only tiers 1, 2 or 3; the “demonstrates a rationale” test is not available. The REL Central summary of ED guidance states the same rule in applied form: interventions under Title I, section 1003 must have strong, moderate or promising evidence, while other programs under Titles I through IV can rely on tiers 1 to 4. A particular competition may add its own requirements, so the notice of funding opportunity for the program is the document that sets the tier an applicant needs. Related background is in the funding opportunity announcement entry.
What it funds or requires
ESSA evidence tiers do not fund anything by themselves. They are a standard that an application must meet when a program requires, or gives priority to, evidence-based activities. What they require of an applicant is documentation: the intervention, the study or studies behind it, the study design, the outcome that showed a significant effect, and, for tier 4, the logic model and the plan to examine effects.
Application and compliance steps
- Confirm the tier the program allows. Check whether the funding source is section 1003 (tiers 1 to 3 only) or another ESEA program (tiers 1 to 4), then read the notice of funding opportunity for any further condition.
- Locate the study evidence. For tiers 1 and 2, the guidance summary points to WWC design standards, so look for the intervention’s WWC review. WWC also publishes a page for ESSA at ies.ed.gov/ncee/wwc/essa.
- Match the study to a tier. Record the design (experimental, quasi-experimental or correlational), whether it meets WWC standards with or without reservations, the sample, and the statistically significant outcome.
- For tier 4, write the logic model. Name at least one intended outcome tied to a stakeholder need and cite the research on how the activity is likely to improve it. A theory of change is the closest related concept on this site.
- Add the evaluation commitment. The statutory tier 4 test has a second part, ongoing efforts to examine the effects of the activity. A logic model with no evaluation plan describes only half of what the statute requires.
Typical timeline phases
Deadlines are set by each competition, so this page gives the order of work rather than dates. The statute and guidance imply a sequence: identify which tiers the funding stream allows; find and rate the supporting studies; state the tier claimed with its design, sample and outcome; and, if relying on tier 4, add the logic model and the plan to examine effects.
Common mistakes
- Claiming tier 4 for section 1003 funds. The statute excludes the rationale test for that funding stream.
- Stopping at the logic model. Tier 4 also requires ongoing efforts to examine effects.
- Treating any positive result as evidence. Each tier requires a statistically significant effect on student or other relevant outcomes, not just a favorable description.
- Counting a study that does not match the tier. A correlational study without statistical controls for selection bias does not reach tier 3; a quasi-experimental study without baseline equivalence does not reach the moderate tier under the guidance summary.
Related programs and bodies
| Name | Role in relation to ESSA evidence |
|---|---|
| What Works Clearinghouse (IES) | Design standards that the guidance summary uses for tiers 1 and 2; hosts a dedicated ESSA page |
| ESEA Title I, section 1003 (school improvement) | Funding stream limited to tiers 1 to 3 |
| Other ESEA programs under Titles I to IV | May rely on tiers 1 to 4, per the guidance summary |
| REL Central (NCES program) | Publishes the summary of the ED guidance used on this page |
| National Center for Education Statistics | Federal education statistics agency; see the CASRAI guide for what it holds |
For the study designs behind the tiers, see the entry on randomized controlled trials.
FAQ
What are the four ESSA evidence tiers?
Strong evidence (tier 1), moderate evidence (tier 2), promising evidence (tier 3) and demonstrates a rationale (tier 4), defined in section 8101 of the ESEA as amended by the Every Student Succeeds Act.
Which study designs count for each tier?
The statute names an experimental study for tier 1, a quasi-experimental study for tier 2, and a correlational study with statistical controls for selection bias for tier 3. Tier 4 instead requires a rationale based on high-quality research findings or positive evaluation, plus ongoing efforts to examine the effects.
Can tier 4 be used for every program?
No. Interventions funded under section 1003 must meet tier 1, 2 or 3. Other programs under Titles I to IV can rely on tiers 1 to 4, per the guidance summary.
Are the ESSA tiers the same as What Works Clearinghouse ratings?
No. WWC ratings (meets standards with or without reservations) describe study quality. According to the guidance summary, they are used to place a study in tier 1 or tier 2, which also require a large multisite sample and a significant positive outcome.
Sources
- Every Student Succeeds Act, Public Law 114-95, new ESEA section 8101 definition of “evidence-based”: govinfo.gov (checked 2026-10-29).
- REL Central (NCES), “Chapter 3: Requirements for Evidence of Effectiveness and Design Standards,” summarizing ED’s September 2016 non-regulatory guidance: nces.ed.gov (checked 2026-10-29).
- Institute of Education Sciences, What Works Clearinghouse: ies.ed.gov/ncee/wwc (checked 2026-10-29).
