Documentation summary

1. HED publications

Explanation of the history, development, and motivation for third generation HED:

Robbins, K., Truong, D., Jones, A., Callanan, I., & Makeig, S. (2021).
Building FAIR functionality: Annotating events in time series data using Hierarchical Event Descriptors (HED).
Neuroinformatics Special Issue Building the NeuroCommons. Neuroinformatics

Detailed case study in using HED-3G for tagging:

Robbins, K., Truong, D., Appelhoff, S., Delorme, A., & Makeig, S. (2021, May 7).
Capturing the nature of events and event context using Hierarchical Event Descriptors (HED).
NeuroImage Special Issue Practice in MEEG. NeuroImage 245 (2021) 118766.

HED viewers

The HED schema is usually developed in .mediawiki format and converted to XML for use by tools. However, researchers wishing to tag datasets will find both of these views hard to read. For this reason, we provide links to three versions of the schema. The expandable HTML viewer is easier to navigate. Annotators can also use CTAGGER, which includes a schema viewer and tagging hints.

HED web-based schema vocabulary viewers.



standard HED schema

Expandable HTML

Expandable prerelease HTML



Score library schemas

Expandable HTML

Expandable prerelease HTML



3. HED Websites

The following is a summary of the HED-related websites:



HED organization website

HED specification

HED examples and tutorials

CTAGGER executable jar


HED organization

HED specification

HED examples and datasets

HED Python tools

HED Javascript code

HED Matlab code and EEGLAB support

HED web deployment

HED-2G support

CTAGGER resources

Online tools

HED tools

HED-2G support

4. HED working documents

Mapping of HED terms and their descriptions to known ontologies is:

Two other working documents hold portions of the HED-3G specification that are under development and will not be finalized for Release 1: