Which form of evidence provides the strongest basis for clinical practice recommendations when synthesizing multiple trials?

Which form of evidence provides the strongest basis for clinical practice recommendations when synthesizing multiple trials?

• A. Expert opinion
• B. Well-designed randomized controlled trial
• C. Systematic review of RCTs
• D. Single qualitative study

Answer: (C)

When building clinical practice recommendations from multiple trials, the most trustworthy form of evidence is a systematic review of randomized controlled trials. A systematic review uses a comprehensive, pre-planned search to identify all relevant RCTs, applies explicit criteria to select studies, and critically appraises their quality. It then synthesizes the data, often with a meta-analysis, to produce a pooled estimate of effect and to examine consistency across studies. This approach reduces random error from any single trial, increases statistical power, and helps identify how results may vary by population, setting, or study design. The result is a more reliable estimate of benefit and risk than any individual trial can provide. In contrast, expert opinion relies on judgment without systematic synthesis; a single well-designed RCT provides strong evidence but is limited to one study and may not generalize; and a single qualitative study provides depth on experiences or processes but does not quantify outcomes or determine effectiveness across populations.

When building clinical practice recommendations from multiple trials, the most trustworthy form of evidence is a systematic review of randomized controlled trials. A systematic review uses a comprehensive, pre-planned search to identify all relevant RCTs, applies explicit criteria to select studies, and critically appraises their quality. It then synthesizes the data, often with a meta-analysis, to produce a pooled estimate of effect and to examine consistency across studies. This approach reduces random error from any single trial, increases statistical power, and helps identify how results may vary by population, setting, or study design. The result is a more reliable estimate of benefit and risk than any individual trial can provide.

In contrast, expert opinion relies on judgment without systematic synthesis; a single well-designed RCT provides strong evidence but is limited to one study and may not generalize; and a single qualitative study provides depth on experiences or processes but does not quantify outcomes or determine effectiveness across populations.