This study examined the effects of converting from an 8 hour shift system to a 12 hour system on aircraft maintenance personnel. The squadron had converted its 24 hour operations from an 8 hour shift schedule to a 12 hour shift schedule in stages, changing one group first and then another. A smaller third group of workers remained on 8 hour shifts. Individual differences in job related outcomes and situational constraints were measured for all three groups. Results showed that changing from 8 to 12 hour shifts affected worker well being and morale, as indicated by an increase in hospital visits after the switch to 12 hour shifts and the difference in levels of morale between 12 hour shift personnel and those remaining on 8 hour shifts.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.