The European Commission (EC) responded last month to 'Stop Vivisection', a European Citizens' Initiative to phase out animal testing, which was signed by more than one million people. The EC confirmed that it will not replace the existing directive on the protection of animals used for scientific purposes (2010/63/EU), which already matches the level of protection in countries with the most demanding legislation. Yet the citizens' principal argument relates not to animal suffering, but to the limited usefulness of results from animal models.

Citizens concerned about animal welfare may still accept research that is perceived as being of ultimate benefit to humans, but only if it delivers relevant results — a view that evidently helped to mobilize signatures in this case. This is one of only three citizens' initiatives since 2012 that have gathered enough signatures to reach the EC, so the scientific community needs to take its criticisms seriously.

As long as blinding, randomization and appropriate sample sizes are not standard practices in animal research, claims of maximizing its benefits are not credible. Unreliable data from poorly designed studies and publication bias give misleading results on the therapeutic value of candidate drugs, leading to disappointing clinical trials (see, for example, S. Perrin Nature 507, 423–425; 2014). Researchers must aim to do research that stands up to critical scrutiny from all quarters.