One size does not fit all: Guidelines for designing a score sheet for animal experiments - eight essential steps

The EU Directive 2010/63 on the protection of animals used for scientific purposes, as well as the Swiss Animal Welfare Legislation, demand monitoring and documentation of specific aspects of an animal experiment, including welfare-related issues and the (retrospective) assessment of the severity of the procedures that the animals underwent. A score sheet is an efficient tool for the evaluation of the burden of an animal during an experiment and, if properly designed and used, helps adhere to the 3Rs principle. It must be adapted to the specifics of each experiment and explicitly conceived for it. Several score sheet examples have been published; however, some contain fundamental flaws or are designed for specific settings only, requiring modifications to fit other experimental designs. This paper suggests an eight-step procedure to design a score sheet that can be adapted to any animal species and experimental conditions.