60 巻 (2014) 5 号 p. 5_69-5_74
A quantitative, single usability measurement is useful for human-centered design. However, the measurement is commonly not sufficiently conducted upstream (design phase), but it is conducted downstream (evaluation phase) after design development. Therefore, in this article, we propose usability metrics and a severity rating method for use during the design development phase. With the aim to develop an easy method for quantifying usability based on current inspection methods (i.e., usability metrics based on inspection methods, or UMI), we investigated the various aspects of the proposed method. Then, the effectiveness of usability metrics was determined by experiment. We believe that the metrics and methods described in this article will be employed by usability practitioners, including human factor engineers, designers, and usability engineers.