What is the correct rank order of evidence types based on the Hierarchy of Evidence?

The hierarchy of evidence is a framework used to rank the strength of research evidence according to its methodological quality. The correct answer is based on this hierarchy, which emphasizes the importance of review and rigorous study design.

The first entry, "Systematic review of all relevant RCTs," is considered the highest level of evidence because it synthesizes findings from multiple random controlled trials, providing a comprehensive overview of the effectiveness of an intervention. This comparability and aggregation of data enhances the reliability and applicability of the findings.

The second level, "Well-designed RCTs," represents studies where participants are randomly assigned to receive or not receive an intervention, eliminating many biases and establishing a causal relationship. These trials are deemed more robust than other study designs.

The third, "Controlled trials without randomization," while not as strong as RCTs, allows for comparisons between intervention and control groups, providing valuable data even in the absence of random assignment.

Next, "Single descriptive studies" offer insights into specific cases or observations but lack the comparative rigor and power of larger studies.

Finally, "Expert opinion" ranks lowest in this hierarchy, as it is based on personal experiences or insights rather than data-driven evidence, making it the least reliable for informing practice.

This structured order