Usability Textual Data Analysis: A Formulaic Coding Think-Aloud Protocol Method for Usability Evaluation

Think-aloud protocols are among the most standard methods for usability evaluation, which help to discover usability problems and to examine improvements because they provide direct information on a user's thinking and cognitive processes; however, it is often difficult to determine how to analyze the data to identify usability problems because there is no formulaic analysis procedure for textual data. Therefore, the analysis is time-consuming, and the quality of the results varies depending on an analyst's skills. In the present study, the author proposes a formulaic analysis think-aloud protocol method that specifies the procedure for analyzing participants' verbal responses during usability tests. The aim of the proposed think-aloud protocol method was to deliver an explicit procedure using step coding (SCAT) and 70 design items for textual data analysis, and then, the method was applied to a case study of usability evaluation to confirm that the method could extract the target system's problems. By using step coding and 70 design items, the process of extracting usability problems from textual data was made explicit, and the problems were extracted analytically. In other words, the proposed method was less ambiguous. Once a formulaic analysis procedure was established, textual data analysis could be performed easily and efficiently. The analysis could be performed without hesitation after data acquisition, and there were fewer omissions. In addition, it is expected that the procedure would be easy to use, even for novice designers.