The first discussion paper 'Introducing the Longitudinal Study of Australian Children' provided an overview of the study, incorporating descriptions of the rationale for the study, relevance for policy development, the conceptual framework, broad and specific research questions, and an overview of the study design. This second discussion paper outlines progress on Growing Up in Australia since the release of the first discussion paper. It concentrates on providing more detail on the proposed sample design and data collection for the first wave of the study, including information on the development and testing process to date.