I suppose I don't find it to be particularly plausible. Moreover, it seemed that you were discounting the study as offering any evidence at all regarding long-term effects; whereas it seems to me that short-term effects offer weak evidence regarding long-term effects. If we know something is short-term beneficial, that isn't strong evidence of it being long-term beneficial — but it isn't evidence of it being long-term harmful either.
It's worth it to keep looking — I certainly agree that it's a failure of many social interventions to look at only short-term effects, especially when this failure is iterated. That's where we get Campbell's Law from.
(That said, it would be really surprising if deeper investigation of social reality happened to closely confirm the preconceived notions of one particular political faction. I mean, seriously, why that one?)
A piece I saw that Benjamin Todd adapted from THINK's module on charity assessment. Some of you may recall the network's recent launch.
cipergoth said that it should be emphasised that this isn't a trick question where the answer is they all worked or none did.
I thought Round 2 would have no effect and expected Round #5 to have no effect not a negative one, I got 6 out of 8 correct. How well did you do?
I recommend checking out the links and references. Gwern's comment there was also interesting.