1. Kellogg School of Management, Northwestern University, 2001 Sheridan Road, Evanston, IL 60208, USA.
2. Northwestern Institute on Complex Systems, Northwestern University, 600 Foster, Evanston, IL 60208, USA.
3. Datascope Analytics, 180 West Adams Street, Chicago, IL 60603, USA.
4. National Bureau of Economic Research, 1050 Massachusetts Avenue, Cambridge, MA 02138, USA.