Formative assessment is an educational improvement system whose targets are learners, instruction and their evaluation. Quizzes are practical methods to collect basic data to be analyzed in assessment. Online tests of CMS (Course Management System) are expected to help students in taking quizzes as many as times and improve their comprehension. Study logs on CMS are valuable data to understand students' behaviour. The present paper proposes and studies several visualization methods of these logs, not to analyze the students but to analyze the lessons and instruction from view of instructional design.
