Investigation and analyses of internal validity in Danish preclinical research

Birgitte S Kousholt

Animal experimental studies may provide important information that furthers biomedical knowledge and improves patient lives. However, animal experiments have poor reproducibility. There are most certainly several reasons why some experiments may be difficult to repdroduce. One reason is low "internal validity". "The internal validity" refers to the extent to which the design and conduct of an experiment eliminate the risk of bias. If results are biased, clinical trials based on the results will then be based on skewed results. On top of that, the biased animal studies are a source of wasteful use of animals.

There are guidlines on how to plan and report animal experimental research to meet high standards of both research quality and code of conduct. These guidlines contribute to a reduction in the number of animals used in inferior studies. Unfortunately, there are only limited incentives to follow the guidelines. This may be because the internal validity of the animal experimental studies is generally not elucidated and communicated. In Denmark, there are no systematic data that illustrate the internal validity of animal experimental research.

This project uses a thorough, knowledge-based and systematic method, which will clarify if biased-limiting incentives are reported. This is an indirect method used to extract to what extent the studies have incorporated measures which reduce the risk of bias. In addition, information on reporting of 3R initiatives is extracted.

This study is a responsible step in the identification of plausible deficits in implementing reduction in Danish in vivo research. Based on the reults a targeted effort can be initiated to reduce biased animal experiments. This creates awareness, among all stakeholders, and the number of animal experiments which do not adequately use bias-limiting tools will decrease. The attention created will also strengthen the translational value of animal experiments. That is, the value needed to translate knowledge from animal experiments into scientific advancement and improved patient care.

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