Chapter 3 - The validity and translatability of preclinical animal research

There is ample evidence that most preclinical animal research is conducted poorly and does not translate to humans. Significant efforts are underway, therefore, to improve the quality and conduct of animal studies. This chapter considers the various factors with the potential to influence the success of preclinical animal experiments, analyzing them as affecting either internal or external validity. It argues that while certain aspects of internal and external validity can be addressed in preclinical research, a key aspect of external validity cannot—and that is the differences between species. Since all aspects of validity need to be robust for an animal experiment to translate to humans, there is little point in improving other aspects of validity if species differences present an insurmountable challenge to clinical translation.