The returns to skills and the nature of work differ systematically across labor markets of different sizes. Prior research has pointed to worker interactions, technological innovation, and specialization as key sources of urban productivity gains, but has been limited by the available data in...

We introduce new measurement tools to understand the sources of earnings differences across space. Based on the natural language employers use in job vacancy text, we develop granular measures of job tasks and of worker specialization. We find that jobs in larger commuting zones involve greater...