Originally published in 1954, this investigation was designed to explore the formation of cohesiveness within work groups in an industrial setting, and the relationship of cohesiveness to productivity and to group members' mental health and adjustment. A company wide questionnaire survey, involving 228 groups totaling 5,871 workers, was made of production workers' background and attitudes, including working conditions, one's job, people in the work group, supervisory practices, wages, the union, promotions, transfers, and training. Members of highly cohesive groups generally showed less anxiety and less variance in productivity than members of less cohesive groups. Highly cohesive groups differed more frequently and strongly than others from the plant norm of productivity, with deviations toward both higher and lower productivity. The direction of deviation depended on the extent to which group members perceived their company as providing a supportive setting for the group. Group cohesiveness was positively related to opportunities for on the job interaction and to prestige attributed by group members to their own jobs. Within any given group, actual productivity and perceived reasonable productivity showed about the same variance. Similarities in age and education were not significant factors. (LY)