Evidence and ESSA: Why Does it Matter?

Imagine you need a life-saving surgery, and your surgeon has a choice between two procedures to perform. One has a 19% mortality rate, and another has a 10% mortality rate. Your surgeon explains that he is choosing the first procedure because it is easier to do, he is trained in it, and he simply likes it better than the other procedure. Would you put your life in this surgeon’s hands?

We all trust the value of evidence in medicine. So, why don’t we demand evidence-based methods when it comes to education? The Every Student Succeeds Act (ESSA) places strong emphasis on evidence-based practice. The phrase appears 61 times in the law, and many ESSA funding streams are only available for activities that are supported by research. In this blog, we’ll discuss what evidence-based practice means and why it matters, and we’ll review the ESSA’s four tiers of evidence.

What does evidence-based practice mean?

Evidence-based practice means an activity, strategy, or intervention that:

Demonstrates a statistically significant effect on improving student outcomes or other relevant outcomes based strong, moderate or promising evidence. 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 and includes ongoing efforts to examine the effects of such activity, strategy or intervention.

Why does it matter?

A recent policy brief by Chiefs for Change, an education advocacy group, explained the importance of evidence-based practices this way:

Guiding schools and districts toward programs that have clear positive effects and away from trends without track records has great potential to change the academic trajectory for PK-12 students across the country. One example: replacing a math curriculum which lacks all research support with one deemed strong by Tier 1 research could add as much as seven months' worth of student learning. This is also a matter of equity: Where research indicates the potential of a given intervention to significantly reduce achievement gaps, we surely have a pedagogical and moral imperative to employ it if we are able to do so.

We all want our schools and districts to employ resources that will help students succeed. By using rigorous and relevant evidence and assessing the local capacity to implement interventions (e.g., funding, staff, staff skills, stakeholder support), schools are more likely to implement interventions successfully.

What are the ESSA's four tiers of evidence?

ESSA tiers research across four standards that embody varying degrees of methodological rigor, with Tier 1 representing the strongest and Tier 4 the weakest levels of research. ESSA lays out a number of funding streams that are only available if they are used to support activities that have research support. Here are the four categories, with a brief description of each:

Tier 1 – STRONG At least one well designed/well implemented experimental study (i.e., randomized).

Tier 2 – MODERATE At least one well designed/well implemented quasi-experimental study (i.e., matched).

Tier 3 – PROMISING At least one well designed/well implemented correlational study with statistical controls for selection bias.

Tier 4 – UNDER EVALUATION Demonstrates rationale based on high-quality research or positive evaluation that such activity, strategy, or representation is likely to improve student outcomes (i.e., logic model).


For an intervention or activity to be classified within the first three tiers, it must be supported by research that demonstrates a statistically significant effect on improving student outcomes or other relevant outcomes. These three tiers are grouped under the Category 1 evidence level.

Tier 4 falls under Category 2. This category comprises the weakest levels of research and should be used rarely. It is designed for ideas that hold promise but do not yet have an evidence base qualifying for the top three tiers. To use Tier 4 methods effectively, detailed procedures must be established before beginning to use the strategy, program or intervention.

Want to learn more about evidence-based research?

There’s much more to research than defining its category. To better understand how to qualify research-and find out if chocolate really leads to weight loss-read our next blog, 5 Examples of Evidence-Based Research for Academic Programs.