The large literature on costly signaling and the somewhat scant literature on preference signaling had varying success in showing the effectiveness of signals. We use a field experiment to show that even when everyone can send a signal, signals are free and the only costs are opportunity costs,...

We estimate the causal impact of school and classroom gender composition on achievement. We take advantage of the random assignment of Korean middle school students to single-sex schools, co-educational (coed) schools with single-sex classes, and coed schools with mixed-gender classes. Male...

This paper examines non-price competition among colleges to attract highly qualified students, exploiting the South Korean setting where the national government sets rules governing applications. We identify some basic facts about the behavior of colleges before and after a 1994 policy change...