How to Build an Economic Model in Your Spare Time by Hal R. Varian UC Berkeley December 1994 Current version: June 11, 1997 Abstract. This is an essay for Passion and Craft: Economists at Work, edited by Michael Szenberg, University of Michigan Press, 1997. Keywords. Address. Hal R. Varian, Dean, School of Information Mangement and Systems, UC Berkeley. Web page http://www.sims.berkeley~hal How to Build an Economic Model in Your Spare Time Hal R. Varian