Review sampling settings are set on the project level with a default set on the Organization level. This means you can set the default review sampling percentage for your organization in the Organization Settings tab and you will have the option to override the default when creating a project or after you create a project in the Project Settings tab.
Review Sample Size
This will control the percent of segments that will be assigned for review.
For example, a document with 100 segments that is in a Project with review sampling set to 20% will result in 20 segments being assigned for review.
Exclude exact matches
This is an extra control on the scope of which segments are eligible for review. With this setting enabled, 100% TM matches and document repetitions will be excluded from the scope.
For example, a document with 100 segments, 40 document repetitions, and is in a Project with review sampling set to 20% will result in 12 segments being assigned for review.
Where they are set...
This sets the default for all Projects in the organization.
NOTE: Updates to the review sampling in the Organization Settings do not update existing Project's settings
You will see the Organization settings default populated in the Project Settings on project creation.
After project creation, you can go back and made changes to the project's review sampling settings. Projects that have already been sampled, will not be impacted by changes to settings.