Standard Article

Exact Randomization Technique

Statistical Theory and Methods

  1. Rob Moir

Published Online: 15 JAN 2013

DOI: 10.1002/9780470057339.vae051.pub2

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

Moir, R. 2013. Exact Randomization Technique . Encyclopedia of Environmetrics. 2.

Author Information

  1. University of New Brunswick, New Brunswick, Canada

Publication History

  1. Published Online: 15 JAN 2013


The exact randomization technique is a distribution-free, computationally-intensive statistical method of dealing with small samples and uncertain distributions. The technique was first proposed by Fisher in 1935 as a method of dealing with small biological samples. Because of the computational demands, only the recent development of powerful desktop computers permits researchers to regularly use this technique. Suppose two sets of observations are recorded and labeled according to whether they come from a treatment or a control group. The concept of randomization is based on the observation that a conventional test statistic (e.g. a t statistic) can be interpreted as a typical draw from the distribution of test statistics that would be generated from randomly shuffling the treatment and control labels among the observed data. In fact, the exact randomization test is essentially a controlled example of bootstrapping.