> 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/scenario-syntax/overriding-variables.md).

# Overriding Variables

This article explains how to **override variables** in Model Reef scenarios.

You will learn:

* How variable overrides work when each scenario is a separate model.
* Which parts of a variable you typically change by scenario.
* How to keep overrides traceable and easy to review.

Because each scenario is its own model, overriding variables is simply editing them in that scenario model.

{% stepper %}
{% step %}

### Variable copies per scenario

When you duplicate a model to create a scenario:

* Every variable is copied into the new model.
* The copy in Scenario A is independent from the copy in Scenario B.
* Editing a variable in one scenario does not affect any other scenario.

This makes variable overrides straightforward and safe.
{% endstep %}

{% step %}

### Common variable overrides between scenarios

Typical differences between scenario models include:

* Revenue volumes or growth rates.
* Prices, discounts or take up rates.
* Staff hiring, headcount and salary levels.
* Opex efficiency or cost out assumptions.
* Capex timings and project scope.
* Tax rate or incentive assumptions.

Any variable field can be changed in a scenario model, including timing, formula and type if needed.
{% endstep %}

{% step %}

### How to override a variable in a scenario model

To override a variable for a particular scenario:

* Open the scenario model (for example `Client - FY25 - Upside`).
* Open the **Variable Editor** for the variable you want to override.
* Adjust drivers, presets, formulas or timing as needed.
* Save the changes.

The scenario model recalculates its P\&L, Balance Sheet, Cashflow, Cash Waterfall and valuation based on the override.
{% endstep %}

{% step %}

### Tracking and documenting overrides

To keep overrides easy to understand later:

* Use **notes** on the variable to explain scenario specific logic.
* Tag key variables with labels such as `Scenario override`, `Upside change` or `Downside change`.
* Keep naming and category structures consistent across scenarios so matching variables are easy to recognise.

This is essential when many variables differ between scenarios.
{% endstep %}

{% step %}

### Minimising unnecessary overrides

Try to avoid overriding variables where:

* The input should remain the same across all scenarios (for example statutory tax rules in some jurisdictions).
* The impact is minor compared to major scenario levers.

Fewer, well targeted overrides make it clearer what really drives the difference between scenarios.
{% endstep %}
{% endstepper %}

***

## Related articles

* [Linking Drivers to Variables](/syntax/drivers-syntax/linking-drivers-to-variables.md)
* [Overriding Drivers](/syntax/scenario-syntax/overriding-drivers.md)
* [Equity Variables: what is, rules, what it affects](/help/drivers-variables-and-timing/equity-variables.md)
* [Investment & Transactions](/how-tos/investment-and-transactions.md)


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