Animal methods bias is the preference for animal-based research methods or the lack of expertise to adequately evaluate nonanimal methods. 

Animal methods bias can affect the quality or fairness of nonanimal research assessments, including peer reviews of manuscripts and grant applications. In publishing, animal methods bias 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. 

Researchers may choose to use nonanimal experimental models for a variety of reasons, including their ability to reliably mimic human biology and clinical responses, their advantages over comparable animal-based approaches, and their lower resource and ethical burdens. Despite these advantages, many researchers still perceive animal use as the “gold standard” in biomedical research and testing, which can lead to unfair assessments of nonanimal studies or unjustified requests for animal experiments.

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.