In contrast to the dominant, computational view of decision support, the conversational view emphasizes the sharing and interpretation of information as a social and interactive process. The communication space, including all the interactions between professionals during a working day, is largely ignored by informatics. Yet it is in need of support: it is interruption-driven, has poor communication systems and poor practices. Information technologies (such as a decision support system or an EPR) require formalizations of information processes for them to operate, while communication systems (such as a telephone) do so much less. Proper design for the communication space requires balancing the need to formalize with the benefits of supporting informal communications. 'Common ground' is a concept which helps to decide when to opt for informational and when for communication solutions. Two communicating agents always share a 'common ground' of background knowledge that does not require explication. Creating common ground (between people or between people and IT) costs time. Yet in the absence of a pre-established common ground, this needs to be established when performing a task, which is risky and expensive.