Age and Earnings in the Labour Market: Implications of the 1980s Labour BulgeW.B.ArthurauthorCurrent theories offer conflicting guidance on how demographic changes in the labour force affect earnings and advancement over the working career. Human capital theory, as reflected in Welch (1978) for example, would predict that larger age cohorts than normal would earn less throughout their careers.1 If, as human-capital theory assumes, earnings are based on productivity, then the increased competition for complementary inputs must lower productivity and hence salaries. Members of larger labour cohorts will therefore have lower age-earnings profiles.1983Palgrave MacmillanBook Section