Methods for applying blinding and randomisation in animal experiments

Laboratory Animals, vol. 58, pp. 419–426

Abstract

Blinding and randomisation are important methods for increasing the robustness of pre-clinical studies, as incomplete or improper implementation thereof is recognised as a source of bias. Randomisation ensures that any known and unknown covariates introducing bias are randomly distributed over the experimental groups. Thereby, differences between the experimental groups that might otherwise have contributed to false positive or -negative results are diminished. Methods for randomisation range from simple randomisation (e.g. rolling a dice) to advanced randomisation strategies involving the use of specialised software. Blinding on the other hand ensures that researchers are unaware of group allocation during the preparation, execution and acquisition and/or the analysis of the data. This minimises the risk of unintentional influences resulting in bias. Methods for blinding require strong protocols and a team approach. In this review, we outline methods for randomisation and blinding and give practical tips on how to implement them, with a focus on animal studies.

Authors 3

1. PS Verhave Aachen Animal Welfare Body Leiden

   Leiden University Medical Center

   Affiliation as printed

   Animal Welfare Body Leiden, Leiden University Medical Center and Leiden University, Leiden, the Netherlands

2. Robin van Eenige Aachen Division of Endocrinology Department of Medicine, Leiden University Medical Center Einthoven Laboratory for Experimental Vascular Medicine

   Leiden University Medical Center

   Affiliation as printed

   Division of Endocrinology, Department of Medicine, Leiden University Medical Center, Leiden, the Netherlands

   Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands

3. Ivo ACW Tiebosch corresponding

   Utrecht University

   Affiliation as printed

   Animal Welfare Body Utrecht, Utrecht University, Utrecht, the Netherlands