Advocating for Generalizability: Accepting Inherent Variability in Translation of Animal Research Outcomes

Advancing scientific discovery requires investigators to embrace research practices that increase transparency and disclosure about materials, methods, and outcomes. Several research advocacy and funding organizations have produced guidelines and recommended practices to enhance reproducibility through detailed and rigorous research approaches; however, confusion around vocabulary terms and a lack of adoption of suggested practices have stymied successful implementation. Although reproducibility of research findings cannot be guaranteed due to extensive inherent variables in attempts at experimental repetition, the scientific community can advocate for generalizability in the application of data outcomes to ensure a broad and effective impact on the comparison of animals to translation within human research. This report reviews suggestions, based upon work with National Institutes of Health advisory groups, for improving rigor and transparency in animal research through aspects of experimental design, statistical assessment, and reporting factors to advocate for generalizability in the application of comparative outcomes between animals and humans.

The Impact of Social and Behavioral Factors on Reproducibility in Terrestrial Vertebrate Models

The use of animal models remains critical in preclinical and translational research. The reliability of the animal models and aspects of their validity is likely key to effective translation of findings to medicine. However, despite considerable uniformity in animal models brought about by control of genetics, there remain a number of social as well as innate and acquired behavioral characteristics of laboratory animals that may impact on research outcomes. These include the effects of strain and genetics, age and development, sex, personality and affective states, and social factors largely brought about by housing and husbandry. In addition, aspects of the testing environment may also influence research findings. A number of considerations resulting from the animals' innate and acquired behavioral characteristics as well as their social structures are described. Suggestions for minimizing the impact of these factors on research are provided.

Improving Replicability, Reproducibility, And Reliability In Preclinical Research: A Shared Responsibility

Reproducible and reliable scientific investigation depends on the identification and consideration of various intrinsic and extrinsic factors that may affect the model system used. The impact of these factors must be managed during all phases of a study: planning, execution, and reporting. The value of in vivo (animal) research has come under increasing scrutiny over the past decade because of multiple reports documenting poor translatability to human studies. These failures have been attributed to various causes, including poor study design and execution as well as deficiencies in reporting. It is important to recognize that achieving reproducible and reliable preclinical research results is a joint responsibility that requires a partnership between the investigative team and the animal care and use program staff. The myriad of intrinsic factors, such as species, strain/substrain, age, sex, physiologic and health status, and extrinsic factors, including temperature, humidity, lighting, housing system, and diet, need to be recognized and managed during study planning and execution, as they can influence animal physiology and biological response. Of equal importance is the need to document and report these details. The ARRIVE and PREPARE guidelines were developed by concerned scientists, veterinarians, statisticians, journal editors, and funding agencies to assist investigative teams and scientific journals manage and report on intrinsic and extrinsic factors to improve reproducibility and reliability. This issue of the ILAR Journal will focus on the various extrinsic factors that have been recognized to confound animal research.