label-studio/docs/source/includes/annotation_ids.md

How Label Studio saves results in annotations

Each annotation that you create when you label a task contains regions and results.

• Regions refer to the selected area of the data, whether a text span, image area, audio segment, or something else.
• Results refer to the labels assigned to the region.

Each region has a unique ID for each annotation, formed as a string with the characters A-Za-z0-9_-. Each result ID is the same as the region ID that it applies to.

When a prediction is used to create an annotation, the result IDs stay the same in the annotation field. This lets you track the regions generated by your machine learning model and compare them directly to the human-created and reviewed annotations.