The amount of training retired to learn a job is an important factor in determining the pay of blue-collar and nonsupervisory white-collar jobs. Training requirements, however, do not play as large a role in determining pay for these jobs as for Professional jobs. Although some of the highly paid blue-collar jobs have lengthy training requirements, most of the training occurs on the job during an apprenticeship, or possibly in a technical school, rather than in a college or university.The rate of pay assigned to a particular blue-collar or nonsupervisory white-collar job is mainly influenced by skill requirements. Highly skilled jobs pay significantly more than jobs requiring less skill. However, pay levels also are influenced by working conditions, physical demands, job hazards, and other characteristics that may make jobs unpleasant or difficult to perform Pay increases for nonsupervisory white-collar workers are closely related to pay increases for blue-collar employees, and the pay for both groups is influenced by collective bargaining. When a union raises the wage level of one group, the wages of the other groups usually are raised at the same time.