> For the complete documentation index, see [llms.txt](https://docs.cortex.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cortex.io/guides/migrations-and-modernization/validate-data.md).

# Validate data after migration

[Data verifications](/configure/settings/entity-settings/verification.md) ensure that entity data in the catalog (e.g., ownership and metadata) stays accurate over time. 

As a best practice after migrating data (for example, migrating services from spreadsheets into Cortex), we recommend scheduling a data verification to ensure your entities are up to date.

## Set up a data verification after a migration

You must have the `Configure verification periods` permission to set up a verification.

1. In Cortex, navigate to the [Entity verification settings](https://app.getcortexapp.com/admin/settings/entities/verification) page. Click **+Add verification period**.
2. In the side panel, fill in the fields:
   * **Start date** and **End date**: Enter the start and end dates for the verification period. 
     * The start date cannot be in the past. The end date must be at least one day after the start date.
     * Choose a timeframe that is reasonable based on the number of entities that each team will need to verify. 
   * **Name**: Enter a descriptive name, e.g., `Validate data after migration`.
   * **Verification instructions**: Enter clear and concise instructions that will appear on the entity's details page, e.g., `These entities were recently imported from spreadsheets. Please review and verify whether they're accurate.`
   * **Require reason for verification**: Check this box to require the user to include a reason if they confirm that the entity's data is invalid. 
     * We recommend requiring a reason, as it will allow you to quickly understand what needs to be fixed on an entity.
   * **Team member roles responsible for verification**: Select which Cortex users will be responsible for verifying data.
     * If you select multiple roles, any of those users can verify data.
     * If you do not select a team member role, any user who owns the entity can verify data.
   * **Entities to verify**: Specify which entities the verification policy applies to. 
     * You can select a specific entity type to include (for example, you could apply the verification to all entities of the type `service`) or if your entities have groups assigned, you can filter by specific groups.
     * Under **Advanced options**, you can use CQL to refine which entities you want to verify. For example, you might narrow your selection to entities created in the last two weeks:\
       `entity.created() < duration("P2W")`
3. Click **Create verification period**.

Within a few minutes of saving the verification period, it will be visible to admins in the list of verifications on the [Entity verification settings page](https://app.getcortexapp.com/admin/settings/entities/verification). Entity owners will receive notifications to verify their entities.

## Remediate entities with incorrect data

After setting up the verification period, you can [create a CQL report to view all entities that have been verified as incorrect](/configure/settings/entity-settings/verification.md#view-all-unverified-or-incorrect-entities) using a prebuilt CQL report template.

Cortex also offers a prebuilt [Scorecard template to flag entities that have not yet been verified](/configure/settings/entity-settings/verification.md#flag-unverified-entities-via-scorecard).