Like many economists who care about American families struggling to make ends meet, I spend a good amount of time thinking about how parents can earn more income to give their children better opportunities and reduce stress in their daily lives. But my real mission is one you hear less about in the debate over income inequality. For families to make their way to a better life, it’s not enough to earn more. They’ve got to keep and grow their earnings, too.

Savings and assets — homes, cars, retirement funds — are launching pads to something better, even as they cushion against today’s inevitable emergencies. But for generations, policies to help families build the savings and assets they need to give their children a better life have created a persistent and widening gap in net worth between white families and African-American and Latino families.