Abstract We have been asked to consider the feasibility of piloting a Citizens’ Basic Income (CBI): a basic, unconditional, universal, individual, regular payment that would replace aspects of social security and be introduced alongside changes to taxes. Piloting and evaluating a CBI as a Cluster Randomized Control Trial (RCT) raises the question of whether intervention and comparison groups would be in equipoise, and thus whether randomization would be ethical. We believe that most researchers would accept that additional income, or reduced conditions on receiving income would be likely to improve health, especially at lower income levels. However, there are genuine uncertainties about the impacts on other outcomes, and CBI as a mechanism of providing income. There is also less consensus amongst civil servants and politicians about the impacts on health, and substantial disagreement about whether these would outweigh other impacts. We believe that an RCT is ethical because of these uncertainties. We also argue that the principle of equipoise should apply to randomized and non-randomized trials; that randomization is a fairer means of allocating to intervention and comparison groups; and that there is an ethical case for experimentation to generate higher-quality evidence for policymaking that may otherwise do harm.