The development of a usability evaluation method for educational systems or applications, called the self-report-based sequential analysis, is described herein. The method aims to extend the current practice by proposing self-report-based sequential analysis as a new usability method, which integrates the advantages of self-report in survey research (e.g., questionnaires and interviews) and lag sequential analysis to evaluate educational systems or applications and further understand students' operational process patterns of behaviors toward the systems' interfaces. An empirical study using a drill-based game as a platform was conducted to test the effectiveness of the self-report-based sequential analysis method. The results showed the critical mediators and behavioral transfer patterns among the different area of interests during the students' overall operational process behaviors. For example, the health points and badges as rewards served as critical mediators between the rewards and feedback and health points and countdown timer, respectively. The self-report-based sequential analysis helped explore the participants' operational process behaviors in the area of interests, and why behaviors shift on area of interests that can assist to diagnose the inappropriate arrangement of area of interests. Suggestions are provided based on the results.