For human operators supervising a complex system it is crucial to have a powerful and flexible information presentation system. In order to reduce the cognitive load operators often need to tailor the information presentation to their information needs in particular task situations. The data being presented to the operator is always on a certain type of scale. The scale type of data is determined by how values are assigned to the properties of the system being supervised and it restricts the operations that can be legitimately applied to data. In this paper the concepts of scales and scale transformations are discussed in relation to supervisory control. It is argued that an important subset of tailoring activities can be understood in terms of scale transformations.