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Confidence Interval or P-Value Similarities and Differences between Two Important Methods of Statist

Statistic significance, also known as p-value, and CI (Confidence Interval) are common statistics measures and are major at the statistical analysis of studies in medicine and life sciences. These measures provide complementary information about the statistical probability and conclusions regarding the clinical significance of study’s findings. This article is intended to describe the methodology of the methods, compare between the methods, assert their suitability for different needs of study results analysis and explain situations in which each method should be used.

Key words: Confidence Interval, Statistical Significance, Clinical Significance, Statistical Inference.


  1. Prel J.B., Hommel G., Rohrig B., Blettner M. Confidence interval or p-value? DtschArztebl Int. 2009; 106(19):335-339.

  2. Wolfe R., Hanley J. If we’re so different, why do we keep overlapping. When 1 plus 1 doesn’t make 2. CMAJ 2002; 166:65-66.

  3. Land P.N.D., Chaset W.W. Statistics notebook: entry IV.A: confidence interval. Optometry and vision science. American academy of optometry, 1992; 69(8):658-661.

  4. Young K.D., Lewis R.J. What is confidence? Part 2: detailed definition and determination of confidence intervals. Ann Emerg Med 1997;30:311-318.

  5. Altman D.G., Machin D., Bryant T.N., Garder M.J. Statistics with confidence: Confidence intervals and statistical guidelines (2nd ed.). 2000. London: British Medical Journal Books.

  6. Belia S., Fidler F., Williams J., Cumming G. Researchers misunderstand confidence intervals and standard error bars. Psychol Methods 2005; 10(4):389-96.

  7. Bird K.D. Confidence intervals for effect sizes in analysis of variance. Educational and Psychological Measurements 2002, 62; 197-226.

  8. Estes W.K. On the communication of information by displays of standard errors and confidence intervals. Psychonimic Bulletin & Review 1997, 4; 330-341.


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