A large new study offers clues about how lower-income children can rise up the economic ladder.

Social scientists have made it a priority in recent years to understand upward mobility. Money itself is ... important. Other factors – like avoiding eviction, having access to good medical care and growing up in a household with two parents – may also make upward mobility more likely. Now there is another intriguing factor to add to the list, thanks to a study ... in the academic journal Nature: friendships with people who are not poor. "Growing up in a community connected across cl