Requirement Levels are based on RFC 2119. The EAS does not consider synonyms in order to avoid confusion.

As mentioned elsewhere, Requirement Levels are used for score computation. However, since text information cannot be used in a mathematical formula, there must be a way to assign each Requirement Level a numeric value.

The EAS comes with pre-defined Requirement Level values, which you can modify. You can edit Requirement Level Rating Values in the Requirement Level Ratings dialog, which is reachable via the 'Edit' menu.

To edit a value, just select the respective row and press the 'Edit' button.