Actually, there are things I believe, based on no studies at all but that's why they are called beliefs. The evidence bar for UBI must not be just high but extremely high because of the profound effect it can have on societies, for better or worse. My country's been through communism. And if a scientist looked at us 10-20 years after the regime started, I wouldn't be surprised if the conclusion was as positive as in the basic income pilots - literacy rate jumped through the roof, poverty was greatly reduced, practically no unemployment. We all know how these stories end but my father still reminisces about the "good old days when everyone had a job" sometimes.

On the other hand, I don't think my bar is set that high. Like I mentioned in another comment here, the biggest problem with these pilots is not the limited scope or the strings attached. The problem is that they are the exact reverse of the UBI version in question. Most of the pilots can be described as "rich giving money to the poor". The UBI version that we're discussing here is "poor giving money to the rich". Because that's exactly the net effect when you dismantle welfare programs and distribute the money to everyone - those who have been on welfare till now will receive less. Those who weren't will get more.