The nurse is reviewing the results of a literature search and wants to

QUESTION

The nurse is reviewing the results of a literature search and wants to determine the strength of the evidence. In which order, from strongest to weakest, should the nurse analyze this data?

1. Single, well-conducted clinical trials
2. Single descriptive or qualitative study
3. Expert opinion of authorities or committees
4. Single correlational study or observational studies
5. Systematic reviews of randomized and nonrandomized trials
6. Systematic review of descriptive studies including qualitative
7. Systematic review of correlational studies or observational studies

ANSWER:

Correct Answer: 5, 1, 7, 4, 6, 2, 3

Beginning with the highest level and going to weakest, the hierarchy to evaluate evidence is as follows: (1) evidence from systematic review or meta-analysis of all relevant randomized clinical trials (RCTs) or evidence-based clinical practice guidelines based on systematic reviews of RCTs; (2) evidence obtained from at least one well-designed RCT; (3) evidence obtained from well-designed controlled trials without randomization; (4) evidence from well-designed case-control and cohort studies; (5) evidence from systematic reviews of descriptive and qualitative studies; (6) evidence from a single descriptive or qualitative study; and (7) evidence from the opinion of authorities and/or reports of expert committees.