Replacement, Reduction & Refinement – University of Copenhagen

Replacement, Reduction & Refinement

Researchers’ attitudes to the 3Rs—An upturned hierarchy?

By N. Henrique Franco, P. Sandøe, & I. A. S. Olsson (2018)


Animal use in biomedical research is generally justified by its potential benefits to the health of humans, or other animals, or the environment. However, ethical acceptability also requires scientists to limit harm to animals in their research. Training in laboratory animal science (LAS) helps scientists to do this by promoting best practice and the 3Rs. This study evaluated scientists’ awareness and application of the 3Rs, and their approach to other ethical issues in animal research. It was based on an online survey of participants in LAS courses held in eight venues in four European countries: Portugal (Porto, Braga), Germany (Munich, Heidelberg), Switzerland (Basel, Lausanne, Zurich), and Denmark (Copenhagen). The survey questions were designed to assess general attitudes to animal use in biomedical research, Replacement alternatives, Reduction and Refinement conflicts, and harm-benefit analysis. The survey was conducted twice: immediately before the course (‘BC’, N = 310) and as a follow-up six months after the course (‘AC’, N = 127). While courses do appear to raise awareness of the 3Rs, they had no measurable effect on the existing low level of belief that animal experimentation can be fully replaced by non-animal methods. Most researchers acknowledged ethical issues with their work and reported that they discussed these with their peers. The level of an animal’s welfare, and especially the prevention of pain, was regarded as the most pressing ethical issue, and as more important than the number of animals used or the use of animals as such. Refinement was considered more feasible than Replacement, as well as more urgent, and was also favoured over Reduction. Respondents in the survey reversed the ‘hierarchy’ of the 3Rs proposed by their architects, Russell and Burch, prioritizing Refinement over Reduction, and Reduction over Replacement. This ordering may conflict with the expectations of the public and regulators.

The 3Rs Principle - Mind the Ethical Gap!

By I. A. S. Olsson, N. H. Franco, D. M. Weary & P. Sandøe (2012)
Altex Proceedings, 1/12, Proceedings of WC8. 


Over the 50 years since they were first proposed, the 3Rs (Replacement, Reduction, Refinement) have made a tremendous impact. These principles seem to unify concerns for better science with causing less harm to animals. The ideas behind the 3Rs are so intuitively compelling that it is tempting to believe that full implementation is merely a matter of time, and once the 3Rs are widely implemented, the public will fully support any continued laboratory animal use that is deemed necessary. In this paper, we argue that these conclusions are unlikely to be correct, in part because the 3Rs are rich in ambiguities, and any implementation requires resolving the dilemma that promoting one R will sometimes directly or indirectly conflict with promoting another. For example, should Reduction be conceived in absolute or in relative numbers? Is it really possible (or desirable) to use relative Replacement (i.e., switching from a higher to a lower species)? Which of the 3Rs should receive priority?

Until now, some scholars have focused on identifying Replacements for the use of live animal experiments in research, while others have focused on Reduction in the number of animals used and Refinements in procedures such that animals experience less harm. Meaningful contact between these camps may be limited, however. In some cases, the goals of Reduction and Refinement actually conflict, as, for example, in the choice to re-use animals (and hence reduce total animal usage) or to avoid re-use (and hence avoid the negative effects of repeated exposure to harmful procedures). We conclude that there is now a need for a more thorough ethical discussion on how to resolve these issues.

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