in a dual labour market, a secondary sector is characterized by short-term employment relationships, little or no prospect of internal promotion, and the determination of wages primarily by market forces. in terms of occupations, it consists primarily of low or unskilled jobs, whether they are blue-collar (manual labour), white-collar (e.g. filing clerks), or service industry (e.g. waiters). these jobs are linked by the fact that they are characterized by "low skill levels, low earnings, easy entry, job impermanence, and low returns to education or experience."