To gain insight into the potential importance of including singles into our analyses when we aim at quantifying the degree of sorting along education, just consider the analogy between the marriage market and the labor market. The former matches marriageable individuals, while the latter matches companies with job seekers. By excluding unmatched individuals on the labor market, i.e., the unemployed individuals from an analysis, we ignore the fact that adjustment on the labor market to the changing demand for goods and services can be achieved not only by an adjustment on the intensive margin (i.e., by the changes in the number of hours worked by the employed individuals), but also by the adjustment along the extensive margin (i.e., by the changes in the total number of employed individuals).