IDEAS home Printed from https://ideas.repec.org/a/plo/pone00/0059202.html
   My bibliography  Save this article

The Impact of Study Size on Meta-analyses: Examination of Underpowered Studies in Cochrane Reviews

Author

Listed:
  • Rebecca M Turner
  • Sheila M Bird
  • Julian P T Higgins

Abstract

Background: Most meta-analyses include data from one or more small studies that, individually, do not have power to detect an intervention effect. The relative influence of adequately powered and underpowered studies in published meta-analyses has not previously been explored. We examine 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. Methods and Findings: For 14,886 meta-analyses of binary outcomes from 1,991 Cochrane reviews, we calculated power per study within each meta-analysis. We defined adequate power as ≥50% power to detect a 30% relative risk reduction. In a subset of 1,107 meta-analyses including 5 or more studies with at least two adequately powered and at least one underpowered, results were compared with and without underpowered studies. In 10,492 (70%) of 14,886 meta-analyses, all included studies were underpowered; only 2,588 (17%) included at least two adequately powered studies. 34% of the meta-analyses themselves were adequately powered. The median of summary relative risks was 0.75 across all meta-analyses (inter-quartile range 0.55 to 0.89). In the subset examined, odds ratios in underpowered studies were 15% lower (95% CI 11% to 18%, P

Suggested Citation

  • Rebecca M Turner & Sheila M Bird & Julian P T Higgins, 2013. "The Impact of Study Size on Meta-analyses: Examination of Underpowered Studies in Cochrane Reviews," PLOS ONE, Public Library of Science, vol. 8(3), pages 1-8, March.
    • Handle: RePEc:plo:pone00:0059202
    DOI: 10.1371/journal.pone.0059202
    as

    Download full text from publisher

    File URL: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0059202
    Download Restriction: no
    File URL: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0059202&type=printable
    Download Restriction: no
    File URL: https://libkey.io/10.1371/journal.pone.0059202?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    References listed on IDEAS

    as
    1. Gordon H Guyatt & Edward J Mills & Diana Elbourne, 2008. "In the Era of Systematic Reviews, Does the Size of an Individual Trial Still Matter?," PLOS Medicine, Public Library of Science, vol. 5(1), pages 1-3, January.
    Full references (including those not matched with items on IDEAS)

    Citations

    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
    as


    Cited by:

    1. Stanley, T. D. & Doucouliagos, Chris, 2019. "Practical Significance, Meta-Analysis and the Credibility of Economics," IZA Discussion Papers 12458, Institute of Labor Economics (IZA).
    2. Catherine J. Carter-Snell & D. Gaye Warthe, 2023. "“Stepping Up”: A Decade of Relationship Violence Prevention," Social Sciences, MDPI, vol. 12(9), pages 1-15, September.
    3. Rennert, Lindiwe, 2022. "A meta-analysis of the impact of rail stations on property values: Applying a transit planning lens," Transportation Research Part A: Policy and Practice, Elsevier, vol. 163(C), pages 165-180.
    4. Sarah Fischer & Shannon Hyder & Arlene Walker, 2020. "The effect of employee affective and cognitive trust in leadership on organisational citizenship behaviour and organisational commitment: Meta-analytic findings and implications for trust research," Australian Journal of Management, Australian School of Business, vol. 45(4), pages 662-679, November.
    5. Christian Gunge Riberholt & Vibeke Wagner & Jane Lindschou & Christian Gluud & Jesper Mehlsen & Kirsten Møller, 2020. "Early head-up mobilisation versus standard care for patients with severe acquired brain injury: A systematic review with meta-analysis and Trial Sequential Analysis," PLOS ONE, Public Library of Science, vol. 15(8), pages 1-33, August.
    6. Vibeke Koushede & Carina Sjöberg Brixval & Lau Caspar Thygesen & Solveig Forberg Axelsen & Per Winkel & Jane Lindschou & Christian Gluud & Pernille Due, 2017. "Antenatal small-class education versus auditorium-based lectures to promote positive transitioning to parenthood – A randomised trial," PLOS ONE, Public Library of Science, vol. 12(5), pages 1-17, May.
    7. Seetha Anitha & David Ian Givens & Rosemary Botha & Joanna Kane-Potaka & Nur Liana Binti Sulaiman & Takuji W. Tsusaka & Kowsalya Subramaniam & Ananthan Rajendran & Devraj J. Parasannanavar & Raj Kumar, 2021. "Calcium from Finger Millet—A Systematic Review and Meta-Analysis on Calcium Retention, Bone Resorption, and In Vitro Bioavailability," Sustainability, MDPI, vol. 13(16), pages 1-14, August.
    8. Navin Kumar & Kamila Janmohamed & Kate Nyhan & Laura Forastiere & Wei Hong Zhang & Anna Kågesten & Maximiliane Uhlich & Sarah S.M. Van de Velde & Joel J.M. Francis & Jennifer Toller Erausquin & Elin E, 2021. "Sexual health and COVID-19: protocol for a scoping review," ULB Institutional Repository 2013/320377, ULB -- Universite Libre de Bruxelles.

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Akinori Hisashige & Nobuyuki Shimizu & Yasuyuki Seto, 2021. "Cost-Effectiveness of Early Oral Feeding Following Total Gastrectomy," Global Journal of Health Science, Canadian Center of Science and Education, vol. 13(1), pages 1-64, January.
    2. Alex Eble & Peter Boone & Diana Elbourne, 2017. "On Minimizing the Risk of Bias in Randomized Controlled Trials in Economics," The World Bank Economic Review, World Bank, vol. 31(3), pages 687-707.

    More about this item

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:plo:pone00:0059202. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: plosone (email available below). General contact details of provider: https://journals.plos.org/plosone/ .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.