A data dictionary is a centralized repository that provides information about specific data such as meaning, relationships to other data, origin, usage, and format. A data dictionary stores metadata that defines and describes data so that it can be easily understood by anyone who would like to use it or analyze it at a later date. Librarians can assist in building data dictionaries for researchers by working closely with them at the onset of a new research project. The data dictionary – if started at the beginning of a research lifecycle – can assist in the management of research data from the beginning of data capture to the completion of a research study. For example, a data dictionary would be used to define each descriptive heading used when gathering quantitative data as part of a research study.