Research in the area of shift work has found that it produces a variety of negative consequences, specifically, sleep deficiencies, performance decrements, fatigue, gastrointestinal disorders, and social and marital problems. Therefore, management needs to be able to objectively measure the degree of worker satisfaction and the adequacy of particular shift schedules. This paper presents results of a method designed by the U.S. Bureau of Mines to assess these problems in an iron mining company. The site is divided into two groups of plant and pit workers, having two different rotating shift schedules. Informal conversation, a plantwide vote, and survey items clearly indicate that the continuous 28-day-phase advance shift schedule is less accepted by the workers than is the discontinuous 21-day-phase advance shift schedule. Results indicate differences between the two groups on certain variables such as sleep quantity and quality, eating, and physical and mental exhaustion. It is concluded that the survey represents a valid instrument in that it is sensitive to variables known to be affected by working irregular hours, and that it discriminates between the workers on the two different work schedules.