Editorial

Statistics for the Nonstatistician: A Primer for Reading Clinical Studies

Authors: Ishak A. Mansi, MD, FACP

Abstract

In this issue, the Southern Medical Journal presents several articles about understanding and applying evidence-based medicine in clinical practice. One of the more challenging areas for clinicians is statistics. Experienced editors of medical journals have complained of difficulties in understanding all aspects of statistical methods and applications.1Several medical journals and organizations, as well as book authors,2,3 have published articles trying to simplify this complex subject for the busy clinician, including the American College of Physicians, the Journal of the American Medical Association, and theBritish Medical Journal,4–9 from which I have referenced some of the data in the Table on the following page. The objective of the Table is to offer the busy clinician, resident, or academic faculty member a quick reference in reading commonly used statistics in clinical studies. Two other articles in this issue of the SMJ address in more detail some of the common concepts and methods of statistics.

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References

1. DeMaria AN. Lies, damned lies, and statistics. J Am Coll Cardiol 2008; 52: 1430–1431.
 
2. Lang T, Secic M. How to Report Statistics in Medicine: Annotated Guidelines for Authors, Editors, and Reviewers. 2nd ed. Philadelphia, PA, American College of Physicians, 2006.
 
3. Dawson B, Trapp R. Research questions about relationships among variables. In: Basic & Clinical Biostatistics. 4th ed. New York, Lange Medical Books/McGraw-Hill, 2004, chapter 8.
 
4. Doll H, Carney S. Introduction to biostatistics: part 3. Statistical approaches to uncertainty: P values and confidence intervals unpacked. ACP J Club 2006; 144: A8–A9.
 
5. Greenhalgh T. How to read a paper. Papers that report drug trials. BMJ 1997; 315: 480–483.
 
6. Greenhalgh T. How to read a paper. Statistics for the non-statistician. I: different types of data need different statistical tests. BMJ 1997; 315: 364–366.
 
7. Guyatt G, Haynes B, Jaeschke R, et al. The philosophy of evidence-based medicine. In: Guyatt G, Rennie D, eds. Users’ Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice. 2nd ed. Chicago, IL, American Medical Association, 2008, 9–16.
 
8. Primer on probability, odds and interpreting their ratios. Available at: http://www.acponline.org/clinical_information/journals_publications/ecp/mayjun00/primer.pdf. Published 2000. Accessed December 13, 2011.
 
9. Primer on 95% CIs for the number needed to treat. Available at: http://www.acponline.org/clinical_information/journals_publications/ecp/mayjun99/primer.htm. Published 1999. Accessed December 13, 2011.
 
10. Citrome L. Show me the evidence: now what do I do with it? South Med J 2008; 101: 1197.