This report examines the causes and consequences of youth unemployment in Organisation for Economic Cooperation and Development (OECD) member countries. Summarized first is the youth unemployment situation since the 1974/1975 recession. In a section on recent developments in youth labor markets a series of tables and graphs provide data on youth unemployment from 1955 to 1979 for most OECD member nations. Covered in a discussion of the medium-range outlook for youth unemployment are the following topics: an economic-demographic model of youth unemployment, youth unemployment projections for 1980-1981, the impact of demographic changes over the medium term, and labor force participation rates. A microeconomic analysis of youth labor markets is presented. Addressed in the analysis are high turnover rates among youth, the "hard-core" element in youth unemployment, and possibilities for generalizing findings to other OECD member countries. The role of relative wages, dead-end jobs, youth aspirations and the private and social costs of youth unemployment are explored. Appended to the report are a paper focusing on the advantages of using longitudinal data for analyzing youth labor markets and an inventory of measures to assist youth introduced by OECD member nations over the past three years. (MN)