I suspect the choice of candidates ("households earning about $30,000 annually") had a strong impact on the results.

If you're killing yourself working multiple low-paying jobs to barely survive, it makes sense you use a fifth of the gifted $1000 to reduce the hardest working hours. How many percent of those candidates did you expect to entirely safe the $1000 and invest?

What's the conclusion? We better not hand out this money, because then there aren't enough poor people forced to work those low-paying jobs, and the GDP might drop?