Practical overview
When it fits
Use it after generating NER predictions when token-level scores do not show enough about complete entity boundaries, partial matches or entity-type errors.
Who it is for
- Developers and researchers evaluating named-entity recognition models.
- Teams comparing NER predictions with labeled reference sequences.
Documented uses
- Assess whether predicted entities match reference spans and types.
- Review precision, recall and F1 alongside partial, missed and spurious entity counts.
- Break down evaluation results by entity type.
Requirements & limits
The library is open source under the MIT license. The README documents installation with pip.
- The documented input example consists of sentence-level lists of token labels, with reference and predicted sequences.
- Evaluation requires specifying the entity types through the
tagsargument in the example. - Reports distinguish scenarios and include entity counts as well as precision, recall and F1-score.
Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.
Evaluate NER label sequences
Generate an entity-level summary report from reference and predicted NER labels.
Before you start
- Python environment with nervaluate installed using pip.
- Reference and predicted labels arranged as lists of token labels, with each list corresponding to a sentence.
- The entity types to evaluate.
Steps
Install the library with the command below.
pip install nervaluateImport
Evaluatorfromnervaluate.evaluator.Initialize
Evaluatorwith the true labels, predicted labels, the entity types intags, andloader="list".Call
evaluator.summary_report()to display the report, or useevaluator.summary_report(mode='entities')to group results by entity type.
Expected outcome
A report showing evaluation scenarios and measures including precision, recall, F1-score, and counts for correct, incorrect, partial, missed and spurious entities.
Guide limitations
- The documented example uses token-label sequences and requires both reference and prediction labels.
- The guide covers the README's list-input example; it does not establish support for other input formats.
Sources & review
Source record details
- Source availability
- Active
- Sources checked
- 14 October 2026
- Original website title
- MantisAI/nervaluate · Official homepage title · retained in its source language

