Abstract

The debate about the appropriate computer human interface - direct manipulation versus command line - is an old one and a false one. That it regularly arises is a consequence of inappropriate software design. An ideally designed system would freely mix the two.

D.A. Norman's (1988) Design of Everyday Things is condensed to five essential principles which are applicable to the design of interactive statistical systems. These are described and illustrated by the design of the experimental statistical software system called Quail. While the principles apply types of interface they are illustrated primarily for a direct manipulation one.

Examination of these principles continually points to the value of modelling statistical concepts directly in the base software system. It is argued that such a system would be well positioned to freely mix interface styles to best suit the analysis.