| Ref ID | 545 |
| First Author | R. M. Turner |
| Journal | PLOS ONE |
| Year Of Publishing | 2013 |
| URL | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3609745/pdf/pone.0059202.pdf |
| Keywords |
• General medical • Cochrane • Power |
| Problem(s) |
• Weaknesses identified in some Cochrane reviews • Perpetuates citation of poor quality primary study data |
| Article Type | Empirical |
| Article Subtype | Meta-epidemiological analysis |
| First Author Country | United Kingdom |
| Aim | To assess the distribution of power available in studies within meta-analyses published in Cochrane reviews, and investigate the impact of underpowered studies on meta-analysis results. |
| Level of Investigation | Analytical |
| Summary of Findings | In 70% of CDSR meta-analyses, all studies had less than 50% power to detect a 30% relative risk reduction, and only 17% of meta-analyses included at least two studies with at least 50% power to detect a relative risk reduction of 30%. |
| Number of systematic reviews included | 14886 |
| Number of eligible systematic reviews assessed | 14886 |
| Treatment impacted | Yes |
| Treatment impacted description | The results of excluding underpowered studies from meta-analyses correspond to a slight shift towards the null value when underpowered studies were removed, more so under the random-effects model in which small studies have greater influence. |
| Interpretation impacted | No |
| Interpretation impacted description |