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Understanding the science of synthesis

  • John Wallace

Summary

This article covers the basic principles of systematic reviews and meta-analyses while discussing the problems associated with the traditional narrative review. It explores the role of the overview as a formal method of combining information from all relevant studies about a particular health condition. It also describes how the review tries to minimise bias so as to avoid reaching the wrong conclusions from the available research data. Important issues that need to be considered when appraising an overview are outlined. Some terms used in reporting systematic reviews and meta-analyses are introduced, such as risk ratio, mean difference, confidence interval and the forest plot.

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Copyright

Corresponding author

Dr John Wallace, DPhil Reader in Evidence-Based Healthcare, Kellogg College, 62 Banbury Road, Oxford OX2 6PN, UK. Email: john.wallace@wadh.oxon.org

Footnotes

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Declaration of Interest

None.

Footnotes

References

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Akobeng, AK (2005) Understanding systematic reviews and meta-analysis. Archives of Disease in Childhood 90: 845–8.
Beck, AT, Ward, CH, Mendelson, M et al (1961) An inventory for measuring depression. Archives of General Psychiatry 4: 561–71.
Bowers, D (2008) Medical Statistics from Scratch. John Wiley & Sons.
Chalmers, I, Hedges, LV, Cooper, H (2002) A brief history of research synthesis. Evaluation and Health Professional 25: 1237.
Deeks, JJ, Higgins, JPT, Altman, DG (2008) Analysing data and undertaking meta-analyses. In Cochrane Handbook for Systematic Reviews of Interventions (eds Higgins, J, Green, S) 243–96. John Wiley & Sons.
Egger, M, Smith, D, Altman, DG (2001) Systematic Reviews in Health Care. BMJ Publishing Group.
Glasziou, P, Irwig, L, Bain, C et al (2001) Systematic Reviews in Healthcare: A Practical Guide. Cambridge University Press.
Heneghan, C, Badenoch, D (2006) Evidence-based Medicine Toolkit. Blackwell Publishing.
Higgins, JPT, Green, S (eds) (2008a) Cochrane Handbook for Systematic Reviews of Interventions. John Wiley & Sons.
Higgins, JPT, Altman, DG (2008b) Assessing risk of bias in included studies. In Cochrane Handbook for Systematic Reviews of Interventions (eds Higgins, JPT, Green, S) 187242. John Wiley & Sons.
Higgins, JPT, Green, S (2008c) Guide to the contents of a Cochrane protocol and review. In Cochrane Handbook for Systematic Reviews of Interventions (eds Higgins, JPT, Green, S) 5179. John Wiley & Sons.
Lang, A, Secic, M (2006) How to Report Statistics in Medicine. American College of Physicians.
Lefebvre, C, Manheimer, E, Glanville, J (2008) Searching for studies. In Cochrane Handbook for Systematic Reviews of Interventions (eds Higgins, JPT, Green, S) 95150. John Wiley & Sons.
Moher, D, Liberati, A, Tetzlaff, J et al (2009) Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 339: b2535.
Oxman, AD, Guyatt, GH (1988) Guidelines for reading literature reviews. Canadian Medical Association Journal 138: 697703.
Seers, K (2005) Systematic review. In Evidence-Based Practice: A Primer for Health Care Professionals (2nd edn) (eds Dawes, M, Davies, P, Gray, A et al): 101–20. Elsevier Health Science.
Taylor, M, Harris, G (2008) Medical Statistics Made Easy. Scion Publishing.
Thornley, B, Adams, C (1998) Content and quality of 2000 controlled trials in schizophrenia over 50 years. BMJ 317: 1181–4.
Tyrer, P (2008) So careless of the single trial. Evidence-Based Mental Health 11: 65–6.

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Understanding the science of synthesis

  • John Wallace
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