> [!CAUTION]
> **Caution:** This documentation is for Google Ads API **v24** . The latest active version is [**v26**](https://developers.google.com/google-ads/api/reference/rpc/latest/SimulationModificationMethodEnum.SimulationModificationMethod).

Enum describing the method by which a simulation modifies a field.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v24/enums/simulation_modification_method.proto)

| Enums ||
|---|---|
| ## `DEFAULT` | The values in a simulation were applied to the given resource. Overrides on child resources were respected, and traffic estimates do not include these resources. |
| ## `SCALING` | The values in a simulation were all scaled by the same factor. For example, in a simulated TargetCpa campaign, the campaign target and all ad group targets were scaled by a factor of X. |
| ## `UNIFORM` | The values in a simulation were applied to all children of a given resource uniformly. Overrides on child resources were not respected. |
| ## `UNKNOWN` | Used for return value only. Represents value unknown in this version. |
| ## `UNSPECIFIED` | Not specified. |