This paper presents a new interpretation of the educational policy and post-compulsory schooling development during the Fourth French Republic (1945-1958).Apparently,minor changes in the school system organization and in post-compulsory schooling brought about some essential components for the transformation of the school system toward a comprehensive organization, beginning in 1959. The paper shows that contrary to the reformers’assertion in the mid-fifties, the growth of schooling was moderate before 1953. The main elements of change in the context which defines “school problems” lay in the thoughts of the Commissariat au Plan about labor force, and in the development of the french system of social statistics. These elements gave substance to new ideas about the future of french society and the aims of lengthy schooling.