> For the complete documentation index, see [llms.txt](https://docs.usepylon.com/pylon-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.usepylon.com/pylon-docs/platform/custom-fields/field-history.md).
# Field History
Track how field values change over time to monitor trends and identify important shifts in your customer data.
### Overview
Field history tracks changes made to custom field values in Pylon, allowing you to view historical data and analyze trends over time. This is particularly valuable for monitoring key metrics like ARR, health scores, sentiment, and account engagement.
### Formulas
Track field history using account formulas: `GetValue`, `GetValueRelative`, `QueryChange`, and `QueryChangePct`. These formulas let you fetch point-in-time values or calculate changes over time. Learn more about formulas here.
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