Like all other areas of progress and development, the academic field has also seen considerable changes in the modes of imparting knowledge and education. Teaching and learning are no longer limited to classroom sessions where one person takes the center-stage to deliver knowledge, and a group of students remain at the receiving end. The present-day scenario has expanded its wings to more inclusive and innovative methods of teaching, wherein students are allowed to experiment and explore beyond the formally taught knowledge. Problem-based learning (PBL) is one such way of teaching students, where they use their prior knowledge to solve problems. Overview As the name suggests, PBL refers to a learning process where the students gain new knowledge through exploring a research problem in a structured and systematic way. This problem can often be a real-life situation. PBL focuses on being more 'student-centered' than traditional modes, and allows students to partially determine the learning objectives of the course or topic that they are about to learn. Thus, the learning occurs through the skills and techniques that the students obtain to find solutions for a problem, rather than listening to lectures and striving to 'learn' the subject by rote. Trigger The process of PBL begins with a trigger which indicates a problematic situation. The students then start their research and analyze the possible solutions to the given problem. It is critical that the trigger is appropriately focused so that it leads to a definite learning outcome related to the course content. A trigger can be anything from newspaper articles, quotations, movie/video clips, interview citations, photographs, etc. However, the instructor may also choose not to use a trigger, and may instead directly provide a specific situation to the students verbally. Distinctive Features Rather than teaching the theory first and then testing the students on their ability to employ it for practical purposes, this mode of education directly inculcates the practice of implementing theoretical formulae and rules to real-life situations. Presenting Complex/Real-Life Situations The problems are often real-life situations, where the students need to analyze them critically through reference/case studies and research. These problems may not have simple, straightforward, or solitary solutions; they may have several equally valid solutions, depending on variables. Using Prior Learning PBL allows students to use their prior learning to analyze and find a solution for the problem placed before them. By recalling what they have already learned, the students can make assumptions and develop strategies. According to researches, a conflict between new information and previous learning may enhance the learning process. Collaborative Approach While solving a problem, it is not mandatory for the students to get 'the' correct answer, as there may not be one incontrovertible answer or solution to the problem. Instead, the focus lies on the process of finding the solution by working in a group and exploring various possibilities through analytical research work. Role of the Instructor In PBL the instructor steps back from the traditional role of spoon-feeding information to the students. Instead, he/she becomes a facilitator or guide in the process of applying the theory. This role requires a lot of preparation in order to be able to guide students properly by providing information resources, reading/reference list, suggesting research and analysis strategies etc. The instructor may also need to make himself/herself available in person or through email/telephone whenever the students require him/her during the research period. However, it is not mandatory for the instructor to always be with the students. Advantages

• Being more student-centric, this method is more likely to motivate students to learn, since they need to play an active role in analyzing things for a given assignment and gives them much greater freedom than the conventional arrangement.
• Presenting students with real-life situations enhances the problem-solving skills of the students, as opposed to only remembering theoretical knowledge. Learning, therefore, goes beyond bookish knowledge and helps the students face problems that they may encounter further in their own careers.
• Allowing the students to use prior knowledge to solve a new problem ensures deeper understanding. According to researches, learning is enhanced when new information is presented through a meaningful context, and enhances and modifies existing knowledge.
• It demands a collaborative approach towards learning, thus creating an environment in which the students learn to see various approaches to solve the same problem through group interactions. This makes the team responsible for each other, and not just for one's own self.
• Redefining the role of the tutor/instructor, PBL demands a unique relation between the students and the teacher. This, in turn, allows the students to partially determine their course of action with the help of the tutor, making learning more interesting, engaging, and activity-based.

Disadvantages

• While getting introduced to a new topic, the students might not be in the best position to determine what is important for them. It might be too difficult for them to decide their course of action, especially in subjects to which they do not have any prior exposure.
• Students are habituated to classroom sessions with the instructors taking the center stage and transferring knowledge through lectures and notes. All of a sudden, if they are told to analyze a given topic and determine their learning objectives all by themselves, they might get confused or lost.
• Tutors/Instructors are expected to change their conventional roles and prepare themselves to become a guide/facilitator for the students by providing them research and analysis guidance. Some teachers may not find this change of role very comfortable.
• As PBL deals with researching and solving problems, it is essential to generate a proper question, without which the proper learning objectives cannot be determined. If an appropriate problem is not raised it is likely that the students would go out of track and completely miss the actual objective behind the entire course.

Problem-based learning can be adopted to teach single units of a course as well as an entire curriculum.