You can read about his work here and here. I found it quite cheerfully encouraging - he's found that small, practical programs to encourage savings are highly effective, even among the very poor - people traditionally considered to be unthrifty and improvident.
the fact is that poor people can and do accumulate assets, and Sherraden has the data to prove it. Participants in programs of matched savings called IDAs, which resemble 401(k) retirement plans, have saved an average of $33 per month and 71 cents of every dollar that could be saved or matched. Interestingly, the 43 percent of participants monitored whose incomes are below the poverty line save almost as much as other program members, and save a much larger portion of their income.