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Keywords:

  • Cochran–Armitage test;
  • contingency tables;
  • exact tests;
  • E + M p-value;
  • nuisance parameters;
  • unconditional test

Lloyd (Aust. Nz. J. Stat., 50, 329–345, 2008) developed an exact testing approach to control for nuisance parameters, which was shown to be advantageous in testing for differences between two population proportions. We utilized this approach to obtain unconditional tests for trends in 2 × K contingency tables. We compare the unconditional procedure with other unconditional and conditional approaches based on the well-known Cochran–Armitage test statistic. We give an example to illustrate the approach, and provide a comparison between the methods with regards to type I error and power. The proposed procedure is preferable because it is less conservative and has superior power properties. Copyright © 2011 John Wiley & Sons, Ltd.