Wage Trends : collective norms and individual factors - The trend of individual salaries is influenced by collective factors such as the uniform rates of pay resulting from collective wage bargaining or the existence of advancement based on seniority. However, individual factors also come into play, such as promotions by selection, and various events in the professional life of each individual. This article proposes an original indicator for separating these two sets of factors. Wage-earners are divided into homogeneous groups according to age, sex, and socio-professional category. In each group the trend of the median wage is the reference in relation to which individual disparities are measured. . It emerges that these are in fact smaller...