Three Rs Microsite


Reduction Alternatives

Experimental design and sample size can contribute to reducing animal numbers

Experimental design and sample size
can contribute to
reducing animal numbers

Reduction refers to any strategy that will result in fewer animals being used to obtain sufficient data to answer the research question, or in maximizing the information obtained per animal and thus potentially limiting or avoiding the subsequent use of additional animals, without compromising animal welfare.

Reduction of animal numbers can occur by reducing the number of animal experiments conducted and by reducing in the number of animals used in each experiment.

Replication Versus Duplication

When considering whether to repeat an experiment should take place, it is important to distinguish between duplication and replication.

Duplication refers to the unnecessary repetition of animal experiments or tests without sufficient scientific justification. It may occur when an investigator does not know that the experiment has already been carried out or cannot obtain access to the information (for example, if it is proprietary).

Replication refers to the repetition of experiments or tests when scientifically justified. For example, the scientific method demands that research findings be corroborated by the same and other research groups in order to establish the validity of the results.

General Examples of Reduction Alternatives

Reduction can be achieved through careful animal model selection and choice of experimental design.

Consultation with a statistician may also help to identify the best design and sample size.

Reduction strategies can also include considering whether to re-use animals or to share data and tissues. In addition, use of imaging technologies and telemetry can contribute to reduction.

This section has been adapted from the Nuffield Council on Bioethics' Ethics of Research Involving Animals, and CCAC guidelines.

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