Observation is a method of inquiry that requires systematic registering of events without any deliberate attempt to interfere with variables operating in the event which is being studied. Techniques of observation:-This method is used in natural(naturalistic observation) as well as laboratory settings(laboratory observation).Based on the role of the observer “ is divided into participant observation (observer mixes up with the event) and nonparticipant observation (observer has little impact on the study).A student portfolio is a collection of pieces of students work selected to serve a particular purpose. It not only contains the works of the student but also the best works of the students.Student portfolios are often used as an effective instrument for assessing students. Portfolio act as a tool that is based on the technique of observation.?Features of portfolio:-Develops skills among students in evaluating the strength and weaknesses of their work.Provides an excellent opportunity for teachers to observe students know more about them.Helps students to take responsibility for setting goals and evaluating their progress.Creates an opportunity for parents to assess the performance of their children. Additional InformationAssignmentA task assigned by the teacher for the student to complete in a course of time. It may be both in the teacher's presence and absence.WorksheetA paper listing questions or tasks for studentsPaper pencil testA test is organized in the presence of a teacher as a part of a formative assessment.Hence it can be concluded that the portfolio tool is based on the technique of observation.