The Three Rs framework - Replacement, Reduction, and Refinement - provides the ethical and scientific foundation for minimising harm to animals used in research.
The Three Rs have fundamentally shaped laboratory animal welfare over six decades. Genuine progress has been made: in vitro systems, organoids, computer models, and human cell-based assays increasingly replace animal models for many applications. However, the framework's implementation varies enormously between institutions and countries, and significant suffering continues in procedures classified as moderate to severe. The development of harm-benefit analysis frameworks and independent ethical review processes strengthens the Three Rs but requires genuine institutional commitment to welfare as a priority, not just a compliance exercise.