The recently published results of the Altman-funded study on a limited trial of UBI by direct payment have been getting a lot of attention. My own take is similar to (but less polite than) that of Scott Santens (at https://www.scottsantens.com/did-sam-altman-basic-income-experiment-succeed-or-fail-ubi/?ref=scott-santens-newsletter).
Some people suggest that the mechanism (of direct payment rather than as a ‘negative income tax’ or ‘earned income tax credit’) makes a difference; but I don’t see that,
However it’s done I don’t see it as justifiable only on the basis of GDP enhancement but rather on moral grounds as per Gar Alperovitz (eg at https://medium.com/@GarAlperovitz/technological-inheritance-and-the-case-for-a-basic-income-ded373a69c8e ) – which is why I long ago suggested that it should be re-branded as a Universal Fair Inheritance.
Source: Did Sam Altman’s Basic Income Experiment Succeed or Fail?