How to measure and to quantify usability attributes of man-machine interfaces

Several views on man-machine interaction are possible to measure usability attributes: 1) the interaction-oriented view, 2) the user-oriented view, 3) the product-oriented view, and 4) the formal view. Two different possibilities of measurement within the product-oriented view are introduced in this paper. Different types of user interfaces can be described and differentiated by the concept of "interaction points". Regarding to the interactive semantic of "functional interaction points" (FIPs), four different types of FIPs must be discriminated: perceptible versus hidden, and dialog versus application oriented type. Based on the concept of FIPs, the dimensions "feedback" and "interactive directness" can be quantified. Both metrics are helpful to classify the most common user interfaces: command, menu, and direct manipulation. The classification can be validated with the outcomes of several empirical comparison studies.