You may have heard someone refer to “evidence-based” therapies and wondered what this means and whether it points to some therapies being "better" than others. Here I want to explain what is meant by “evidence-based;” which therapies this may be referring to; and what this means for deciding what is “better” or best for clients. For starters, about "evidence": It’s important to know that “evidence-based” refers to a therapy's effectiveness based on a certain kind of evidence.