A primary packaging and publication module within DDI representing the purpose, background, development, data capture, and data products related to a study. In DDI a study is defined as a single coordinated set of data collection/capture activities, such as a one-time survey or a single iteration of a multi-year repeated study (such as one year of a longitudinal survey). The StudyUnit brings together all of the components of the study including the description of its purpose, funding, quality statements, data collection and capture methods and activities, processing activities, and a description of the resulting data (description of its intellectual or logical content plus a description of its physical store).