> For the complete documentation index, see [llms.txt](https://docs.tryterra.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tryterra.co/faq/help-topics/data-api-sdk/data-model-fields-and-units/score-and-enrichment-units-scales.md).

# What units and scales do health and enrichment scores use?

**Provider scores** (activity, sleep, recovery) are unit-less values on a **1-100 scale**, calculated by the providers themselves, so 'good' can differ between brands.

**Data-enrichment scores** are Terra's standardisation across devices, also **0-100**, with two exceptions:

* **Immunity index:** a **0-5 scale**, where closer to 5 means the immune system is more likely compromised.
* **`total_stress_score`:** higher means more accumulated physiological stress.

See [health scores](https://docs.tryterra.co/user-engagement/health-scores).