Assigning constants is also a possibility in the HCPRs.
By assigning a constant to a characteristic, you give it a fixed value. This means that the characteristic is available on the database (for validation, for example) but is no longer displayed in the query (no aggregation/drilldown is possible for this characteristic).
It is either possible on the Target side of the Scenario Tab, or on the Output Tab:
Already existent Master Data or Other Members which are fit the scenario, can be assigned as well:
For more information please refer the Official Help page.