Computerized Machine Tools and the Transformation of U.S. Manufacturing

The diffusion of computerized machine tools in the mid-20th century was a pivotal step in the century-long process of factory automation. We build a novel measure of exposure to computer numerical control (CNC) using initial variation in tool types across industries and differential shifts toward CNC by type. Industries more exposed to CNC from 1970–2007 increased labor productivity and reduced production employment. Workers in more exposed labor markets adjusted by shifting from metal to non-metal manufacturing. Union members were shielded from this job loss, and some workers returned to school to retrain.