> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ES (model variation) lookback (context value)

<Badge color="gray" size="lg">[Lookback](../tags/lookback)</Badge>

|                 |                                                                                                                                           |
| --------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| **Description** | The lookback period for calculating the average of the ES (Model Variation) for the measure “ES (Model Variation) avg”                    |
| **Reference**   | [\[MAR33.5\]](https://www.bis.org/basel_framework/chapter/MAR/33.htm?inforce=20230101\&published=20200327#paragraph_MAR_33_20230101_33_5) |

You can use this context value to override the default lookback period for the ES model variation average.

The default lookback period is "12W" (twelve weeks).