I would be very interested in seeing some sources about "at scale" UBI corresponding to a drop in GDP. My impression is that no countries have come anywhere cl

I would be very interested in seeing some sources about "at scale" UBI corresponding to a drop in GDP. My impression is that no countries have come anywhere close to having a UBI program that could be considered "at scale", so how did they evaluate a corresponding drop in GDP was because of a UBI program?