labour." To this end, it mandates a minimum age of 15, to be relaxed only in exceptional cases, and a minimum age of 18 in hazardous jobs. The only exceptions envisioned for developed countries are employment in conjunction with vocational education programs and "light work" that impinges minimally on youngsters' physical, social, and educational development. The convention does not make a case for the benefits of child labor, nor does it view improvements in health and safety as preconditions for extending these benefits to more young people. Despite the large differences in emphasis, however, it can be argued that U.S. objectives are consistent with Convention No. 138 if there is stricter adherence to the "light work" model—healthy work that does not interfere with education and development.
A major difference between the United States and other industrialized countries appears to be the lack of a coordinated system for helping young people make the transition from student to worker. In countries such as Germany, for example, young people enter apprenticeships that are closely linked to their education and that lead to specific adult jobs. German apprenticeship is formally structured, with a contract that specifies the rights and obligations of the employer and the apprentice and a curriculum that specifies the opportunities for learning that the firm will provide and the knowledge and skills that the apprentice must acquire. Apprentices' learning is tested by a national examination and documented by their employers; on completion, the young workers have credentials that are recognized by all employers. Austria, Denmark, and Switzerland have comparable systems. In contrast, the jobs held by most U.S. children and adolescents, as noted above, are usually disconnected from school curricula and are usually not seen as career stepping stones.
It appears that the proportion of adolescents working in the United States is relatively high compared with other developed countries; see Table 1-1. Caution must be exercised in comparing data among countries, however. What groups are included in the labor force and how terms such as "employed" and "unemployed" are defined differ by country. Methods of data collection, classification, and tabulation differ. Countries also use different reference periods for determining who is employed: Some countries ask about employment on the specific day of the census, and others ask about