HED documentation and other information

This page contains links to various publications and guides for HED tagging. HED has undergone two major transformations from its original form. HEG-3G is the latest version and is in the process of being fully released. Users are strongly encouraged to transition to HED-3G.


HED-3G has a redesigned and streamlined vocabulary for ease of use. The individual terms in the HED-3G are unique, so annotators can use single terms rather than full paths. HED-3G allows library schema for specialized vocabularies and supports infrastructure for capturing experimental design and event-context in a machine-actionable form. HED-3G corresponds to HED versions 8.0.0-alpha.1 and above.

Publications and preprints HED-3G

K. Robbins, D. Truong, A. Jones, I. Callanan and S. Makeig (2020, August 1).
Building FAIR functionality: Annotating event-related imaging data using Hierarchical Event Descriptors (HED).

Documentation and guides HED-3G

HED Hierarchical Event Descriptors: Third generation specification alpha version
googledoc link


HED-2G replaced a single vocabulary hierarchy with orthogonal subtrees, significantly reducing duplication of terms within the hierarchy. HED-2G also introduced parentheses and a significant tool base including online validation. HED-2G includes HED versions between 4.x.x and 7.x.x.

Publications and preprints HED-2G

N. Bigdely-Shamlo, J. Touryan, A. Ojeda, C. Kothe, T. Mullen, K. Robbins (2019).
Automated EEG mega-analysis II: Cognitive aspects of event-related features
NeuroImage vol. 107, February 15, 2020.

N. Bigdely-Shamlo, J. Cockfield, S. Makeig, T. Rognon, C. La Valle, M. Miyakoshi, K.A. Robbins (2016).
Hierarchical Event Descriptors (HED): Semi-structured tagging for real-world events in large-scale EEG.
Frontiers in Neuroinformatics, vol. 10, DOI=10.3389/fninf.2016.00042.

Documentation and guides HED-2G

HED Tagging Strategy Guide


HED-1G is the original incarnation of hierarchical event descriptors based on CogPO. HED-1G, which includes HED versions less than 4.0.0, is no longer supported. However, the headIT repository contains 13 publicly available EEG studies that have been annotated using HED-1G.

Publications and preprints HED-1G

N. Bigdely-Shamlo, K. Kreutz-Delgado, K. Robbins, M. Miyakoshi, W. Westerfield, T. Bel-Bahar, C. Kothe, J. Hsi and S. Makeig (2013).
Hierarchical Event Descriptor (HED) tags for analysis of event-related EEG studies.
2013 IEEE Global Conference on Signal and Information Processing, 1–4.

T. Rognon, R. Strautman, L. Jett, N. Bigdely-Shamlo, S. Makeig, T. Johnson and K. Robbins (2013).
CTAGGER: Semi-structured community tagging for annotation and data-mining in event-rich contexts.
2013 IEEE Global Conference on Signal and Information Processing, 5–8.

Documentation and guides HED-1G