> For the complete documentation index, see [llms.txt](https://help.modelreef.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.modelreef.io/syntax/drivers-syntax/editing-driver-time-series.md).

# Editing Driver Time Series

This article explains how to **edit driver time series** in Model Reef.

You will learn:

* Where to change driver values.
* How manual edits interact with imports and presets.
* How to keep driver edits auditable.

Driver time series are core assumptions that many variables depend on, so edits should be deliberate and traceable.

***

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{% step %}

### Where to edit driver series

You edit driver values in:

* The **Driver Editor** grid for that driver.
* Sometimes in the Data Library, if you are editing an entry that is treated as a driver.

If the series is read only, it may be fully controlled by imports or restricted logic.
{% endstep %}

{% step %}

### Editing individual periods

To change a single period:

* Open the Driver Editor.
* Click the cell for the period you want to edit.
* Type the new value and press Enter.

The driver updates and all linked variables will recalculate automatically.
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{% step %}

### Editing ranges of periods

You can adjust ranges by:

* Copying and pasting values across multiple periods.
* Using fill tools where supported.
* Pasting blocks of values from an external spreadsheet.

This is useful when you have a planned path for prices, volumes or growth that you want to drop in as a block.
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{% step %}

### Interaction with imports and presets

If the driver is partly or fully imported:

* Historical segments may be read only if they are tied to external systems.
* Forecast segments may remain editable, allowing you to adjust the forward path.

If the driver is controlled by a preset:

* Some presets allow manual overrides of the resulting series.
* Others lock the series, requiring changes at the preset parameter level instead.

The editor will indicate which cells are editable.
{% endstep %}

{% step %}

### Keeping driver edits auditable

Because driver changes can affect many variables:

* Use notes to explain significant edits or structural changes in the time series.
* Tag important drivers so they appear in review workflows.
* Avoid making major changes without recording why they were made.

This helps reviewers and future you understand how the model evolved.
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***

## Related articles

* [Export Options](/syntax/chart-and-table-syntax/export-options.md)
* [Formula Editor Layout](/syntax/formula-syntax/formula-editor-layout.md)
* [Authentication (OAuth)](/help/xero-integration/authentication-oauth.md)
* [Build a Synergy & Integration Model](/how-tos/investment-and-transactions/build-a-synergy-and-integration-model.md)