We develop a theory of labor markets with four features: search frictions, worker productivity shocks, wage rigidity, and two-sided lack of commitment. Inefficient job separations occur in the form of endogenous quits and layoffs that are unilaterally initiated whenever a worker's...

We study how human capital diversification, in the form of double majoring, affects the response of earnings to labor market shocks. Double majors experience substantial protection against earnings shocks, of 56%. This finding holds across different model specifications and data sets....

We study how labor market conditions affect unionization decisions. Tight labor markets might spur unionization, e.g., by reducing the threat of unemployment after management opposition or employer retaliation in response to a unionization attempt. Tightness might also weaken unionization by...