European Journal of Epidemiology

, Volume 20, Issue 3, pp 213–216 | Cite as

An easy to use method to approximate Poisson confidence limits

  • Bernard BégaudEmail author
  • Karin Martin
  • Abdelilah Abouelfath
  • Pascale Tubert-Bitter
  • Nicholas Moore
  • Yola Moride


Despite the ever larger choice of softwares and statistical packages allowing fast and accurate computation of binomial and Poisson confidence limits, there is always a need for a simple and reliable formula allowing non-computerized computations. The method proposed in this paper is derived from the Freeman and Tukey’s variance stabilizing transformation for a random Poisson variable and adjusted for giving the best fit with the exact Poisson values. Despite its simplicity, allowing its use in any circumstances, this method provides very satisfactory results and a much better fit than classical formula based on the normal approximation, even if a continuity correction is used. It allows computation of Poisson confidence limits both for count or rates and proportions.


Biostatistics confidence intervals Poisson approximation Poisson count 


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Copyright information

© Springer 2005

Authors and Affiliations

  • Bernard Bégaud
    • 1
    • 2
    • 3
    Email author
  • Karin Martin
    • 1
    • 2
    • 3
  • Abdelilah Abouelfath
    • 1
    • 2
  • Pascale Tubert-Bitter
    • 4
    • 5
  • Nicholas Moore
    • 1
    • 2
    • 3
  • Yola Moride
    • 6
  1. 1.Département de Pharmacologie, INSERM U657Université Victor SegalenBordeauxFrance
  2. 2.INSERM U657cedexFrance
  3. 3.CHUcedexFrance
  4. 4.INSERM U472VillejuifFrance
  5. 5.Hôpital Paul BrousseVillejuifFrance
  6. 6.Université de MontréalMontréalCanada

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