Shorter hours and productivity: evidence from bituminous coal

At the turn of the twentieth century, advocates for shorter working hours often claimed that workers were so fatigued by the end of the workday, that shortening daily hours from ten to eight would have little effect on output. This study examines the record for U.S. coal mining, analyzing both state-level and mine-level panel data during the transition to the eight-hour day. The hypothesis of zero effect is easily rejected. Instead, output declined almost proportionately with hours, but advancing technology made up for the lost output fairly quickly. There is some evidence that employment increased when the eight-hour day was adopted, as unionists hoped, but the effect is not precisely measured.