Animal methods bias is when research is unfairly evaluated because it does not include animal-based experiments.

Often caused by peer reviewers with a preference for animal-based research methods or lack of expertise to adequately evaluate nonanimal methods, animal methods bias may occur any time research is evaluated, including by supervisors, regulators, animal research oversight committees, and the media. In manuscript peer review, it can cause delays in publication or force authors to publish in lower-impact journals. It may also lead early-stage researchers to pursue animal methods because of the impression that they must do so in order to publish and progress their careers. 

Nonanimal research approaches like organ chips and organoids are gaining prominence due to their ability to reliably model human biology and disease, improve clinical translation, and replace animal use. Animal methods bias is one barrier standing in the way of their broader adoption. 

The Coalition to Illuminate and Address Animal Methods Bias (COLAAB) is an international coalition of researchers and advocates formed in 2022 to develop strategies to address this phenomenon.