Robin Dion is a research psychologist at Mathematica Policy Research, which has offices in Washington, D.C., and Princeton, N.J. She is the principal investigator for a federally funded research project, Strengthening Families with a Child Born Out-of-Wedlock. Contact Mathematica Policy Research.

Kathryn Edin is professor of public policy and management at Harvard University’s John F. Kennedy School of Government. She is co-principal investigator for “Couple Dynamics and Father Involvement,” a qualitative study of 75 low-income married and unmarried couples with young children in Chicago, Milwaukee and New York City.

Elizabeth Marquardt is director of the Center for Marriage and Families at the Institute for American Values. She is co-editor of When Marriage Disappears: The New Middle America (2011) and author of Between Two Worlds: The Inner Lives of Children of Divorce.

William Frey, a senior demographer at the Brookings Institution, analyzed the census data showing that for the first time fewer than half of American households are headed by married couples.

Andrew J. Cherlin is a demographer at Johns Hopkins University who has commented on demographic data involving marriage and families.

The Coalition for Marriage, Family and Couples Education is dedicated to making marriage education widely available. Diane Sollee is director.

Child Trends is a nonprofit, nonpartisan research center dedicated to improving children’s lives. One focus of its studies is marriage and family.

The American Association for Marriage and Family Therapy is the professional association for the field of marriage and family therapy. The organization represents the professional interests of more than 50,000 marriage and family therapists throughout the United States, Canada and abroad.

The Marriage & Religion Research Institute archives data about marriage from a number of sources. It also posts links to scholars around the country.