Evidence-based interventions are practices or programs that have evidence to show that they are effective at producing results and improving outcomes when implemented. Under ESSA, there are four tiers, or levels, of evidence.

The definitions of the first three categories are based solely on study methodology and design but not the applicability to a district’s context.

Tier 4 is the base of the pyramid because this is where the majority of evidence lies for interventions implemented by school districts. Numerous educational practices simply do not have strong experimental (strictly quantitative) evidence. Tier 4 helps to build that necessary evidence; it is essential.

We can also think of it this way:

Tiers 1-3 are quantitative focused.

Tier 4 allows for ongoing qualitative and/or quantitative study. Some argue Tier 4 gives a more holistic (and realistic) view of impact from a local district context.