# Threshold

A [severity](/glossary/s/severity) of a particular type is trigged whenever the returned value from the check is higher than the configured threshold, the **baseline**.

The notification threshold / baseline can be defined in several ways.

## Settings

^ Setting ^ Description ^
| Method | `Constant` / `Average` / `Median` / `Deviation` | 
| Percentage | Percentage threshold based on the calculated value. | 
| Deviation | Number of standard deviations | 
| Period | Time period for historical results to include in the calculation. | 
| Offset | Constant to add to the calculated value. |


## Calculations

Static calculations uses a **constant** threshold value.

Dynamic methods calculate the threshold value on the fly, based on a combination of the **type** (percentage or deviation), the **method** (average, median, deviation), the **period** (time frame for historical data to use), and **offset** which is added to the calculated value.

^ Method ^ Calculation ^ Type ^ Example ^
| Constant |  A fixed value. | Static | `25` | 
| Average | [Average](/glossary/a/average). | Dynamic | `120%` of the `average` returned value for the last 2 hours + offset `50`. |
| Median | [Median](/glossary/m/median). | Dynamic | `120%` of the `median` value for the last 2 hours + offset `50`. |
| Deviation | [Standard deviation](/glossary/s/standard_deviation). | Dynamic | `2 standard deviations` + `average` value for the last `2` hours + offset `50`. |