Most of the readily cashable shares in personal hands are held by the richest 20% of Americans, so average families have little extra to spend.

ECONOMIST: From angst to action?

"This is a real challenge to politicians and to managers and the city council because if you invest upfront you only see the cashable benefits down the line and often the benefits don't accrue to the city council, " she said.

BBC: Early intervention schemes create 'dramatic results'