Objective Learnability Estimation Of Software Systems

Learnability is a fundamental usability factor. It is included in several well known and widely used software usability evaluation models such as: IBM's Computer Usability Satisfaction Questionnaire (CUSQ), System Usability Measurement Inventory (SUMI), System Usability Scale (SUS), and others. However, all of them assess learnability only subjectively. Taking into account the fact of presence of differences in perceived duration in interaction between human and computer, development of a new approach targeting usability, as well as learnability, in objective measures could be of great interest. This paper describes our endeavour in pursuing this task. We present our approach to the problem, introduce an instrument for calculating objective learnability out of times of completion, and reveal results of a user study among 101 participants conducted to test adequacy of the method.