Dataset Organization
How IMPACT LNHS datasets are organized within the Centralized Data Repository and in releases.
Behavioral, administrative, demographic, and other tabular data are organized by instrument/measure and provided as standardized CSV files. Tables follow a consistent tidy format, with one row per participant and one column per variable. Participant and visit identifiers provide consistent linkage across tables and data modalities. Data modalities such as neuroimaging with specialized file formats are formatted and organized according to the Brain Imaging Data Structure (BIDS) to ensure consistency across studies and compatibility with standardized processing pipelines (see BIDS Apps).
Data organization at a glance#
| Tabular Data | File-Based Data | |
|---|---|---|
| Structure | Standardized tidy tables (CSV/TSV format) | Modality-specific file types (e.g., NIfTI .nii.gz for MRI) |
| Organization | One table per instrument/measure, containing observations across participants | Participant- and session-level directories (sub-*/ses-*/{MODALITY}/) |
| Examples | Questionnaires, assessments, administrative data, and derived demographics | Raw and processed data in BIDS format |
BIDS folder structure#
Neuroimaging data and derivatives follow the directory structure below. Raw BIDS data are stored under bids/, while outputs generated by processing pipelines are stored separately under derivatives/ by processing pipeline.