Exact one-sided confidence bounds for the risk ratio in 2 × 2 tables with structural zero

Chris J. Lloyd, Max Moldovan

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


This paper examines exact one-sided confidence limits for the risk ratio in a 2 × 2 table with structural zero. Starting with four approximate lower and upper limits, we adjust each using the algorithm of Buehler (1957) to arrive at lower (upper) limits that have exact coverage properties and are as large (small) as possible subject to coverage, as well as an ordering, constraint. Different Buehler limits are compared by their mean size, since all are exact in their coverage. Buehler limits based on the signed root likelihood ratio statistic are found to have the best performance and recommended for practical use.

Original languageEnglish
Pages (from-to)952-963
Number of pages12
JournalBiometrical Journal
Issue number6
Publication statusPublished - 1 Dec 2007
Externally publishedYes


  • Buehler procedure
  • Exact confidence limit
  • Nuisance parameter

ASJC Scopus subject areas

  • Statistics and Probability
  • Statistics, Probability and Uncertainty

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