2005 Volume 11 Issue 1 Pages 4-14
The origins of the Three Rs (reduction, refinement, replacement) concept of alternatives to animal experiments are briefly reviewed, and examples are given of achievements and grounds for hope in the application of the concept, as well as of causes for concern. Attention is then focused on validation, the process whereby test methods are independently evaluated for the reliability and relevance for their stated purposes. Some problems which currently confront the validation process are identified, and a recent proposal that an analogous invalidation process is needed, is discussed. Finally, emphasis is placed on the need for active collaboration in the middle ground, to advance the welfare of both humans and animals.