# Standard categorizations

Nestor provides a wide choice of tools to categorize articles:

[![image.png](https://doc.nestor-edp.org/uploads/images/gallery/2023-06/scaled-1680-/w8wsArfxAWDPsiNu-image.png)](https://doc.nestor-edp.org/uploads/images/gallery/2023-06/w8wsArfxAWDPsiNu-image.png)

For a specific article, categories are available and may be corrected in the [metadata module](https://doc.nestor-edp.org/books/editor-guide/page/the-metadata-module "The metadata module").

<table border="1" id="bkmrk-category-name-partic" style="border-collapse: collapse; width: 100%;"><colgroup><col style="width: 16.9356%;"></col><col style="width: 83.0644%;"></col></colgroup><tbody><tr><td>**Category name**</td><td>**Particularities**  
</td></tr><tr><td>Expertise fields</td><td>- Tree structure
- Used to categorize articles <span style="text-decoration: underline;">and</span> users, to improve editors/referees matches for a given article

</td></tr><tr><td>Article types  
</td><td>- Flat list
- Used for workflow configuration, see [article type configuration](https://doc.nestor-edp.org/books/editorial-office-guide/page/configuration-of-article-types).

</td></tr><tr><td>Sections</td><td>- Flat list

</td></tr><tr><td>Topical issues</td><td>- Flat list

</td></tr></tbody></table>

These categories may be used in combination to:

- handle specific workflows (especially article types and [custom fields](https://doc.nestor-edp.org/books/editorial-office-guide/page/special-categorizations-custom-fields "Custom fields"))
- perform [specific searches](https://doc.nestor-edp.org/books/editor-guide/page/advanced-and-saved-searches) on articles
- display [visual flags](https://doc.nestor-edp.org/books/editorial-office-guide/page/flags) on article pages and article lists
- [process data](https://doc.nestor-edp.org/books/editor-guide/page/articles-lists-views-and-exports) about your journal