There is an obvious research evidence gap in the evaluation of an experimental, sustained UBI, which is considered the ‘gold standard’ for evidence.

“There is a shortage of evidence that meets most or all of the definitional features of a UBI, and the interventions covered by this report vary significantly. To arrive at conclusions at what may occur if all core features were unified into UBI policy, reviews have synthesized evidence from interventions that may not meet the most stringent definitions of universality or unconditionality. Existing experiments with cash payments that are defined as universal often require recipients to have a sufficiently low income to qualify. Additionally, universal programs rarely provide support at a level that would allow people to meet their basic needs. A truly universal program may produce significantly different results based on increased coverage and a change in the identity of recipients to those who are less vulnerable.3,8 Given the feasibility challenges of implementing a universal program at scale, modelling studies may account for heterogeneity in populations and contexts may improve an understanding of the impacts of hypothetical policy reforms. Specifically, these methods can estimate how differences in household circumstances and complex interactions with tax and benefit systems may impact intervention effects.”