What would be an acceptable limit ? 10 years ? in that span you're free to plan long project, even raise children in the same place long enough they can develop habits, friends, without too much stress.
I think we could get some insights even with a broken test. But it has to be made by open minded scientists other wise people will interpret it as final truth.
Problem is that a "good economy" is a subjective idea. It won't matter if open-minded scientists review it 'cause people are going to interpret the results how ever they want anyways.
Edit: I'm not really aiming to contradict you. I would like to see it analyzed in an unbiased manner.
I think it's completely useless. The only results I care about are in the long term (30+ years). This is essentially a 2 year salary giveaway. Not even close to UBI.