The Brain Imaging Data Structure (BIDS) project is a data structure standard initiated by researchers at Stanford University with feedback from the applicable research communities. It allows researchers to more easily structure and share study data within and between research groups. BIDS provides guidelines for structuring data using specific metadata files, dictionaries and file naming conventions. BIDS ensures that enough metadata required to analyze data is accessible, while eliminating that which is unnecessary. Basic metadata is encoded in the folder structures, as well as replicated within the file names. From only the name of the file, for example, one can determine the subject, session, task or modality to which the file refers (Gorgolewski et al., 2016).
The initial BIDS specification was developed for fMRI and related behavioral data, however, BIDS now supports several other modalities. Others are currently in the development process.
The original BIDS specification, along with links to other helpful resources that span several modalities can be found here.