Technology has enabled educators to design courses and programs to improve learning outcomes and has benefited constructivist online environments through collaboration, group work and problem-based learning. As part of this process, assessment has developed from the use of standardized tests to the deployment of an array of instruments: portfolios, online tests, solving problematic situations, rubrics, online questionnaires and so on; but, without a thorough analysis of the set of tools most appropriate in each case. It is important to distinguish between summative and formative assessment. Summative assessment provides information about a student's achievement of specific learning objectives but when the aim is to improve teaching and learning, assessment is formative. This type of assessment serves students as well as instructors in many concrete ways. Students can use feedback from formative assessments to help them know what they have not yet mastered and what they need to study on further. With the information provided by formative assessment, instructors can change their instruction to be more effective and efficient and to target students who need further help. Although formative and summative assessments serve different purposes, they should be used ultimately within an integrated system of assessment, curriculum, and instruction. In this paper we focus is to analyze a summative and formative assessment system in a b-learning environment. We worked with a group of students of 2nd year of Engineering. Each student could choose between traditional assessment, through a written test at the end of the unit, or a system of multiple measurements that include diverse assessment tasks; and could change from one method to the other. An analysis on personal tracking form provides information about: the mark obtained by the student in the unit, student performance in each of the activities, the best activity performed by the student and score distribution. Besides, each student can monitor his performance through his personal tracking form and can improve his participation in some of them if necessary.