# Calibration phases

Calibration phases collect baseline EEG data before, during, or after stimuli phases. 

We recommend keeping calibration phases in your experiments, particularly if you intend to use performance metrics in your analysis.

When you add a calibration phase to your experiment, it automatically includes:

* a 15-second eyes open and eyes closed condition,
* a default instructions screen,
* a countdown, and 
* a fixation cross. 

You can also edit a calibration phase to:

* change the duration of the eyes open or eyes closed condition, and 
* disable the eyes open or eyes closed condition. 

*You cannot add new elements to a calibration phase; this is so calibration phases can be analyzed together and treated the same in your data download.*

![](https://lh5.googleusercontent.com/qmJnU0qSJCLHf6-NORf3xc248x2RF5eixdW9kx4V2QfJWDab_xZGznNS2hc-NHy_kOjgxQJHf1-jBF30xlmGnr5TcLVb-bIlLPfsLD61TRu2if_CvTLlbo30s_Bzi6d6_bTTB1yY=s0)

<br>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://emotiv.gitbook.io/emotivpro-builder/building-an-experiment-in-builder/calibration-phases.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.