You should consider using a field value when the list of allowed values is mostly static or shared across all case types. A field value is a rule that defines a single value for a field that is used in multiple places in an application. Field values are useful when the list of values does not change frequently or when the same values are used in different case types. Reference: https://community.pega.com/knowledgebase/articles/data-management-and-integration/86/field-values