If the Census Bureau proceeds with a recently released plan, then in a few years’ time, we will know very little about how the contours of family life are changing.

We will not even know whether marriage and divorce rates are rising or falling. For all the talk of evidence-based policy, the result will be that important debates on issues including family law, welfare reform, same-sex marriage and the rise of nontraditional families will proceed in a statistical void.

Much of what I, an economist who has studied family issues, and my colleagues in this field have learned about recent trends in marriage and divorce has come from questions in the American Community Survey. It asks people whether they have given birth, married, divorced or been widowed in the past year. Their answers allow demographers to track marriage and divorce rates by age, gender, race and education.