Arrange the following levels of evidence (based on ASHA, 2004) in order of credibility:

Question

Quizplus · Accepted Answer

1. Well-designed meta-analysis of >1 randomized controlled trial
2. Well-designed randomized controlled study
3. Well-designed controlled study without randomization
4. Well-designed quasi-experimental study (including single-case experimental designs [SCED] such as multiple baseline design across participants or behaviors)
5. Well-designed non-experimental studies, i.e., correlational and case studies
6. Clinical experience of respected authorities
7. Expert committee report, consensus conference
This hierarchy is based on the principle that the methodological rigor of the study design directly impacts the credibility of the evidence. Randomized controlled trials (RCTs) and meta-analyses of such trials are considered the gold standard in evidence-based practice because they minimize bias and allow for the strongest inferences about causality. As you move down the list, the potential for bias increases, and the strength of the evidence for causality decreases. Expert opinions and consensus conferences provide valuable insights but are considered less reliable than empirical evidence because they are more susceptible to bias and do not typically undergo the same rigorous scientific evaluation.

Arrange the Following Levels of Evidence (Based on ASHA, 2004)