I think that isn't a correct assumption either.
40 yeas is a long time. Longer than many HN readers here have been alive.
In the last 40 years, how many times has the government performed an about-face on some economic policy or whatever? Too many times for someone to just throw away their career until sufficient time has passed that is becomes part of society. That may take an entire generation (see Social Security in the US, which now is a permanent fixture).
That could be a generation or longer before knowing the actual effects, and by then (as-with Social Security) it'll be practically too late to make a course correction.
1) Even now, plenty of people take into account the possible dissolution of Social Security or (more likely) changes to its benefit formula in their financial planning.
2) Longer time horizons could always have a hypothetical effect. You say a half century of a policy can't predict a hundred years of a policy; someone can just as well say a hundred years of a policy can't predict two hundred years of a policy.
In the long run, though, we're all dead, and the economic landscape is going to be so radically different in a century that it's pointless to predict how a particular policy will fare then. Someone in 1934 making predictions of the effects of Social Security in 2034 would be so far off as to not even be wrong. See, for example, Alf Landon's criticisms of the program then, which don't correspond at all with what its critics today don't like about it.
It wasn't that 40 years of policy won't be enough to convince people to trust in said policy - it's the "promise" of a 40 year policy that isn't enough to convince people to trust in said policy.
Just telling people to trust the policy will be held strong for a least the next 40 years will not automatically convince people to quit their jobs and all the other possible outcomes of UBI. People who've grown up and spent a major portion of their life without UBI will likely remain skeptical, and mostly will not depend wholly on it for income.
Rather, it will, possibly take a generation of people growing up with UBI all their life before we start to see the actual societal changes UBI might affect. By then, it might be too late to make a change since there will be a generation of people who've come to depend on the government's hand for their basic needs.
They provide lower bounds on the amount of time you can offer a guaranteed income without adverse effects on people's employment. Going to an extreme, if you offer people a 40 year UBI and they don't quit, then that's pretty damn strong evidence. 3 years offers some evidence; for particular subpopulations with short time horizons, if they keep on working for three years on UBI, I'd bet almost arbitrary amounts of money they'll keep on working indefinitely.
> No. If you make $1k from a job and $1k from a pilot program each month, you spend the $1k from the pilot on legitimate bills and now you have $1k to spend however you like. The study can't trace that money. (This isn't to say everyone on UBI uses it for drugs, rather, it's to point out that you cannot deduce they don't just by tracing the way the transfer payments are spent)
I believe these studies rely on self-reported alcohol etc consumption. The issues with self-reported consumption are already well-known and well-characterized.
> No kidding. You gave someone several thousand dollars no strings attached in a situation where neither taxes nor inflation would rise as a result.
These things are always worth verifying. One of the criticisms against a UBI is that it'll create a population of depressed losers who never interact with society. If people's lives and happiness are improved, that addresses that criticism.
> What UBI skeptical people want to know is where is the proof that we can afford to tax ourselves to pay ourselves, where is the proof that it won't hurt long term productivity, and where is the proof that it doesn't cause inflation. A 120 person 36 month trial program cannot answer any of these questions.
Could anything short of a full UBI implementation work as proof for you? If not, can you suggest what would? If, say, you took a random selection of 1000 people and promised them a lifelong UBI, and their labor force participation and levels of happiness stayed the same over the first ten years of the program, would that serve as proof to you?