Organizations are struggling to choose from or combine the different business process management paradigms offered in today's BPM landscape, such as workflow management, dynamic case management and straight through processing. The field of declarative processes seems to be able to address this challenge by offering a unified approach to business process modeling, providing variable amounts of flow at execution time and different levels of autonomy to the actors based on models using a single formalism. The notion of declarativity in business processes seems to be ill defined and is often treated as a black and white distinction. However, a number of quite different formalisms have been developed that are broadly agreed to be declarative. This paper proposes a number of qualitative characteristics to characterize the declarative nature of process modeling formalisms. The characteristics are evaluated by applying them to a number of relevant process modeling formalisms, both imperative and declarative, and we discuss how these characteristics can be utilized to create business processes that offer activity flows that are known up front where needed, and allow ad hoc approaches to offer experts freedom and to support impediment driven approaches in an STP context.