> For the complete documentation index, see [llms.txt](https://revstack.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://revstack.gitbook.io/docs/getting-started/inclusion-process/define-annotation-attributes.md).

# Define annotation attributes

## What is an annotation attribute?

Annotation attributes are custom-defined tags or labels used to categorize and gather information within documents in your systematic review. They help structure the data by allowing users to assign relevant characteristics, such as:

* Study type (e.g., clinical trial, meta-analysis)
* Risk of bias assessment
* Outcome measures
* Population size
* Etc.

By defining annotation attributes, you ensure consistency in data extraction, facilitate later stages of analysis, and take advantage of automatic generation of summary tables and bias summary figure.

## Create an annotation attribute

<figure><img src="/files/5ERnnZTQS0MwTfcXAmdz" alt=""><figcaption></figcaption></figure>

To create a new annotation attribute:

{% stepper %}
{% step %}
Navigate to the "Manage annotation attributes" section in your collection settings.
{% endstep %}

{% step %}
Click the "Add a new attribute" button.
{% endstep %}

{% step %}
Enter a name and description for the attribute.
{% endstep %}

{% step %}
Define whether the information collection is mandatory for all documents included in the review.
{% endstep %}

{% step %}
Choose a highlight color.
{% endstep %}

{% step %}
Select the attribute type (e.g., text, numeric, categorical (tags or list), bias).
{% endstep %}

{% step %}
Click "Create" to confirm the addition
{% endstep %}
{% endstepper %}

{% hint style="info" %}
Different types of annotation attributes:

* T**ext:** Allows assigning a textual value to an annotation.
* **Number:** Allows assigning a numeric value to an annotation.
* List: Allows you to assign a textual value from a list of predefined values to an annotation. The list of the attribute's values is not editable once created.
* Tags: Allows you to assign one or more text values from a predefined list to an annotation. New values can by added dynamically.
* Bias: Allows you to collect information for bias analysis (High, Unclear, Low), and then automatically generate the bias summary figure.
  {% endhint %}

## Edit an annotation attribute

To edit an existing annotation attribute:

{% stepper %}
{% step %}
Navigate to the "Manage annotation attributes" section in your collection settings.
{% endstep %}

{% step %}
Find the attribute you want to modify and click the "Edit" button.
{% endstep %}

{% step %}
Update the name, description and the highlight color as needed and click "Save" to apply the change.
{% endstep %}
{% endstepper %}

{% hint style="warning" %}
For “List” type attribute the category value cannot be modified once the attribute has been created. In the event of an error, you will need to delete and then redo the attribute.
{% endhint %}

## Delete an annotation attribute

To delete an annotation attribute click the dropdown button next to the attribute you want to delete and select "Delete attribute."

{% hint style="warning" %}
Deleting an annotation attribute will remove all associated data extraction from the collection, so proceed with caution.
{% endhint %}