Why Are Power Couples Increasingly Concentrated in Large Metropolitan Areas?
利用PSID数据检验Costa和Kahn的共居假说，发现权力夫妇（双方都有大学学历的夫妇）并不比部分权力夫妇或权力单身更可能迁往大城市，而是大城市中权力夫妇的形成率更高。
Using the Panel Study of Income Dynamics (PSID), we test Costa and Kahn’s colocation hypothesis, which predicts that power couples—couples in which both spouses have college degrees—are more likely to migrate to the largest cities than part-power couples or power singles. We find no support for this hypothesis. Instead, regression analyses suggest that only the education of the husband and not the joint education profile of the couple affects the propensity to migrate to large metropolitan areas. The observed location trends are better explained by higher rates of power couple formation in larger metropolitan areas.