Back in July, this study took a location-based look at the broken American dream. Now the Pew Charitable Trusts look at the problem from the dislocated realm of sweeping percentages:

Forty percent of Americans think it’s fairly common for someone to start off poor, work hard and eventually rise to the top of the economic heap.

In reality, however, only 4% of Americans travel the rags-to-riches path, according to new research from the Economic Mobility Project of the Pew Charitable Trusts. And a great many who are born into the poorest segments of the population are stuck there for life, a finding that suggests the U.S. has much to do to improve social mobility.

One interesting sub-finding: "Despite the debate over the value of a college education, a college degree remains the single biggest predictor that a person will move up the ladder."