A control group would be people tracked without having received any money. The $50/month group doing nearly as well as the $1000/month group implies to me the

A control group would be people tracked without having received any money. The $50/month group doing nearly as well as the $1000/month group implies to me the overall situation in the city changed, and that's the majority of the improvement. Maybe $50 really was enough to flip over the edge, but we can't tell for sure because they don't have a real control group.