Historical study of the age-grade efficiency movement which took firm root in North America and the Antipodes during the early 1900s, in particular the preoccupation of education authorities with “the retardation problem” (the number of scholars over-aged for grade in consequence of their failure to make “normal” annual progress through the course of instruction), importantly contributes to understanding the age-grade homogeneity of modern elementary schools. The following account of mid-twentieth century developments in South Australia seeks to provide comparative insights into measures adopted to reduce retardation in the interests of preserving school order, enhancing pedagogical and bureaucratic “efficiency,” improving access to secondary courses, and alleviating the costs of “laggards” to the state.