No large scale experiment exists for UBI.
There's this set of objections to UBI based around "yes, ok, it works in the small scale, but it'll never work on a large scale".
If we did a large scale experiment, and it confirms that it works, the objections will move to "sure, OK, but it'll never work on a national level".
So let's just implement it and see if it works. If it doesn't work, we can always just go back to letting people starve.
They really, really don't. All the experiments on a small scale show is the trivial conclusion that if you give people some central government funds for a year or two, they tend to be slightly less poor at the end. None of them come remotely close to suggesting that people are so much more productive that they can cover the costs of UBI to people already out of the labour force by choice, never mind those that may choose to exit it in future.
Only if the country still has the ability to change and the economy isn't permanently damaged.
Elderly people already get a UBI in the form of Social Security, and that's politically impossible to cut regardless of whether it's a good or bad idea.
Once you turn it on and people get used to it, you can never turn it off in a democracy.
Small-scale experiments have been quite successful though.
And are absolutely useless to study the very important effects that these kinds of systems have on a nation's economy.
I've looked to history for examples of actual real world attempts to guarantee some minimum quality of life for all citizens of a particular group. They consistently do well for some self selected and committed initial group and then go badly when the doors get flung open to include everyone.
One result I recall hearing about is instituting policies like "You don't work, you don't eat" in order to prevent freeloaders from utterly killing the whole system and taking everyone down with them.
Tale as old as time:
> For even when we were with you, we gave you this rule:“The one who is unwilling to work shall not eat.”
https://www.biblegateway.com/passage/?search=2%20Thessalonia...
>No large scale experiment exists for UBI.
Non sequitur.