> For the complete documentation index, see [llms.txt](https://support.happydemics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.happydemics.com/launch/exposure-data/when-and-why-do-we-use-exposure-data.md).
# When and why do we use exposure data?
Depending on the media channel you use in your campaign, it may be possible to “retarget” respondents who are likely to have been exposed to your ad. This can be done using tools such as tracking pixels, user IDs, broadcasting frameworks, or geographic coordinates.
**Exposure data can be seen as:**
* It helps reassure you and your clients about the ad recall status of respondents within a specific environment.
* It increases the comparability between ad recall and non-ad recall respondents, since both groups are targeted with the same broadcasting strategies.
**Please note:** when you provide exposure data, respondents collection is based on this data, including participants in the control group. This approach is different from most other brand lift providers. However, because our methodology is centered on ad recall, this is not an issue. Our goal is to measure the impact of **actually remembering an ad**, not just the effect of potential exposure.
Depending on the media channels used in your campaigns, different types of exposure data may be available. The table below provides an overview of which data types you can use for each media channel.
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