Problem based learning: a case study in computer ...

Recent Research Developments in Learning Technologies (2005)

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Problem-based learning: a case study in computer science M. García-Famoso ETSE-URV, Av. del Països Catalans, 26, 43006, Tarragona, Spain In engineering-related disciplines the theoretical body of knowledge is first taught to the students, who then use what they have learnt to solve specific problems. The main drawbacks of this approach are lack of motivation and high drop-out and failure rates. This case study uses the PBL approach in an introductory course of computer architecture to overcome the main drawbacks of more traditional teaching schemes. Moreover, through PBL, students develop problem-solving skills, self-directed learning skills and critical thinking, all of which are very important in computer science. The students and the teachers have assessed the experience and the results are very satisfactory in both cases. The failure rate is reduced and students develop their analysis and communication skills. Keywords Problem-based learning; computer science; computer introduction

1. Introduction Nowadays, the new scenario created by the Bologna Declaration (1999), and the establishment of the common European Higher Education Area, has led to important changes in the educational models used at Spanish Universities. Within this framework, innovative teaching methodologies such as Problem Based Learning (PBL) provide new and interesting challenges. One of the most important concerns is the role of students in the learning process. This approach puts students in command of their own learning, and requires them to improve their communication skills, co-operative work abilities and analysis/synthesis capacities. Furthermore, PBL promotes self-learning and increases their interest in lifelong learning activities. The results of applying the PBL techniques are very satisfactory. The method is assessed using questionnaires in which students give their opinion about their learning experience. The statistical analysis of the data reveals that about 90% of students would repeat the experience or recommend it to others. In addition, most of the students consider that the methodology strengthens the social relationships between group members. In the sections below, we first describe the main features of PBL. Then, we explain how PBL is applied in the course: “Introduction to Computer Organization and Architecture”. In Section 4 we show the academic results of the experience and the student and teacher assessment. Finally, Section 5 presents some concluding remarks.

2. PBL as an instructional methodology PBL was first applied in the 60s, in the Faculty of Health Sciences of McMaster University (Canada) [1] and in the School of Medicine of Case Western Reserve University (United States) [2]. The main objective was twofold: to develop problem solving skills and bring learning closer to real medical problems. After these first experiences, many medical and professional schools started to use some form of PBL, for example, Harvard Medical School [3] or, in the Europe, Maastrich University [4]. Finkle and Torp [5] describe problem-based learning as "a curriculum development and instructional system that simultaneously develops both problem solving strategies and disciplinary knowledge bases and skills by placing students in the active role of problem solvers confronted with an ill-structured problem that mirrors real-word problems”. According to this definition, the acquisition of domainspecific knowledge is as important as the development of problem-solving skills and abilities and social skills. Savery and Duffy [6] show that PBL is one of the instructional methodologies that best implements constructivist theories: the students have to take part in tasks and activities in real environments.

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M. García-Famoso: Problem-based learning: a case study in computer science

They have to build and organize their own knowledge, and develop critical thinking. They work in groups through discussion, questioning and group presentations. Table 1 summarizes the main differences between PBL and other teaching strategies. Table 1

Traditional methodologies versus Problem-Based Learning strategies [7, 8].

Traditional methodologies Teacher centered Linear and rational Teacher as transmitter Students as passive receivers Structured environment Individual and competitive learning Assessment is the responsibility of the teacher

Problem-Based Learning Student centered Coherent and relevant Instructor as facilitator or collaborator Students as constructors. Active participants Flexible environment Co-operative learning Assessment is the shared responsibility of the students, the group and the teacher

In PBL, students are presented with a problem with no previous preparation. The students discuss and analyze problem, and list what they know and what they need to know. They determine and locate the resources to be used, and try to generate possible solutions. Finally, they summarize their work, present the problem and justify their solution. The students' performance is self-evaluated, group evaluated and teacher evaluated. In this process, students become responsible for their own learning. The problems are designed to be authentic and to reflect the real word. They are ill-structured and complex, and there is not meant to be only one solution: as new information is gathered, the solution changes. The problems do not test skills; they help to develop the skills themselves.

3. PBL in Computer Sciences The course Introduction to Computer Organization and Architecture is taught for 6 hours a week: three hours of lectures, one hour for problem solving and two hours in the laboratory. The course is held in the first semester of the first year of the Computer Science programme. Its learning objectives are to give “students an in-depth understanding of the inner-working of basic digital computer systems and tradeoffs present at the hardware-software interface. They will become aware of the design process for: instruction set design, computer arithmetic, controller and datapath design, basic memory systems and basic input-output systems.” First of all, before PBL can be used in the classroom, a problem must be designed. It must be in accord with PBL principles and cover the main course objectives. The problem selected was “the full design of a basic-computer system; from the instruction set to the controller and datapath”. In order to test the design, a program –in pseudo-code– was provided. It included input/output operations, vector access and arithmetic operations such as multiplication and division. However, it was divided into various steps or phases, in order to help students organize and plan their work. For each phase, the students are given the problem, a list of specific objectives and a reference list of materials –bibliography, web links, etc.– that pertain to the basic objectives. In each phase, students go back over the problem with new information and knowledge. At this point, the group is likely to reformulate its solution. One of most interesting phases was the last one. In this phase, each group presents and supports its design. They must justify it and respond to the other groups’ questions. All the presentations were recorded on DVD and given to the students so that they could improve their communication skills. The first sessions were spent on some introductory subjects: numerical systems and Boolean algebra, and some basic concepts about PBL and collaborative work in groups. Learning objectives aside, PBL overcomes some of the drawbacks of traditional courses such as the high rate of absence: students are more motivated and show more interest in the subject. Students also develop some additional skills, such as teamwork and communication, which are very important in both academic and professional life –and even in their personal life. Moreover, through PBL, students develop

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problem-solving skills, self-directed learning skills and critical thinking, all of which are very important in computer science. 3.1 The classroom and the technology in PBL One important issue in PBL is access to information and appropriate technology: bibliography, web, simulation tools, projectors, etc. Likewise the learning space must facilitate collaborative work. At present, most universities do not have suitable spaces for PBL. We tried to overcome this drawback by using the lecture room, the library and the laboratories as teaching spaces. Moreover, all the course information –calendar, schedule, resources and general information– were organized in a learning management system: Moodle [9], which can be accessed via web. It also provides some communication tools such as a chat, forum and news. Finally, it makes it possible for students to submit assignments in electronic format. Teachers can view each file, and record grades and comments. Moodle then automatically notifies students by e-mail. In order to improve feedback on student work, we used a TablePC to correct work; it makes a detailed electronic correction of the submitted file. Both students and teachers have access to the corrections and, more importantly, they also have real information about the evolution of students' work. Fig. 1 shows Moodle and an electronic correction.

Fig. 1 The learning management system: Moodle [9]. And an electronic correction made with TablePC.

4. Assessment The course has approximately 50 students divided into nine groups of five or six students. The final evaluation was divided into two parts: the group evaluation (65%) and individual evaluation (35%). We evaluated the reports made by each group and several individual tests. Students also completed an assessment test about their personal opinion of the experience. Finally, we summarise the teachers' opinion. 40%

no-PBL PBL

35% 30% 25% 20% 15% 10% 5% 0% D

F

5 6 7 8 Qualifications

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Fig. 2 The figure shows the results of the final evaluation. The white bars indicate the results of PBL students, and the grey bars students of a traditional methodology (no-PBL). The qualification D refers to those who drop out and the qualification F to the students who fail, that is, their final qualification is under 5.

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M. García-Famoso: Problem-based learning: a case study in computer science

4.1 Evaluation results Fig. 2 shows the results of the final evaluation. We can see the high drop-out (37%) and failure (31%) rates among the students that follow the traditional methodology. These rates decrease significantly among PBL students: only 10% of students dropped out and 5% failed. It may be possible to reduce the number of students in this latter group with more attention from the tutor. The qualifications of the rest of the students follow the same distribution in both groups. 4.2 Student assessment When the course finished, we surveyed the students who participated. The main objective was to get their personal opinion about PBL. The first question was to determine why they chose to try PBL (almost 85% of students tried PBL as an alternative to traditional evaluation). Some of the motives they gave were to improve their ability to work in a group (49%) and to develop new skills (41%). Fig. 3 shows the students' opinion about some of the skills developed. One of main objectives was to motivate the students during the course. We can see that PBL involved students more in the course and motivated them to work in this subject. Perhaps the most important target that PBL achieved was to make students take responsibility for their learning process. Moreover, PBL changed the point of view of many students about their role at university. As far as the students’ ability to work as part of a team is concerned, fig. 3 shows that students tried to participate more in group activities, sharing their ideas and learning from the contributions of others. Furthermore, more than 90% of the students consider that their relationship with the other members of the group is very good or excellent. Their relationships with the other groups also improved. Other important skills that students have improved are self-confidence and their ability to find and use the appropriate resources. Other questions were about the organization and design of the course and the assignments. In general, students consider that the objectives, the contents and the evaluation criteria were suitable. And they made them revise what they had learnt and make connections with the new-learning concepts. PBL motivates me to w ork more in this subject. I feel more involved in this couse because I can organize my w ork. The proposed statements helped me develop new skills. PBL has changed my view of the role of the students. I try to take part in the debates that my group holds. The contributions of my colleagues have been very useful. I have shared ideas and point of view w ith my teacher and colleagues. We have assumed responsability for the learning process. I f eel confident about my ow n skill to select the best resources. I think I can determinate w hat the most important issues of this course are. completely 1 disagree

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completely 6 agree

Fig. 3 We can see some of results of the inquiry. We can see how the PBL increases the students’ motivation and interesting in the course (grey bars). Moreover, how it help students to develop the ability to work on a team (white bars) and the critical thinking skill (striped bars).

4.3 Teacher assessment From the teachers’ point of view, PBL requires teachers to change role: from transmitter to mentor. This involves some difficulties: they have to develop coaching skills. There is also a change in the structure of class time, and the teachers have to redesign the course before it starts.

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In general, the teachers spend most of their time on planning the PBL content and sequence of assignments, providing immediate feedback on students' work, and discussing and evaluating students. It would be difficult to do all the work if there were more than four or five in each group. However, the experience is very satisfying because teachers can see the evolutions of students day by day, and the relationships are closer. All of this can help teachers to avoid conflict and reduce failures before the final evaluation.

5. Conclusions The main objectives at the start of this project were, on the one hand, to reduce the high drop-out and failure rate on this course, and, on the other, to encourage students to become involved in their own learning process. The PBL methodology is regarded as being appropriate to achieve these objectives. Moreover, PBL encourages groupwork and some additional skills such as problem-solving and selfdirected leaning skills. The course has been structured around several assignments that students must resolve in groups. The teacher acts as an assessor instead of a transmitter, which makes the student-teacher relationship more fluid. The final assessment was more positive, both from the students’ and the teachers’ point of view. More that 90% of students not only would do it again, but will recommend it to other students. Finally, in fig. 4, we can observe how some of the benefits of PBL are of considerable value to students: for example, teamwork, problem-solving skills and self-directed learning skills. Global assessment I have improved my teamwork. I have improved relations with colleagues. I have improved relationships with teachers. I have improved my problem-solving skill. I have improved my self-directed learning skills. I have improved my domain-specific knowledge. completely 1 disagree

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completely 6 agree

Fig. 4 There is the students’ opinion about the skills developed with PBL methodology Acknowledgements This work was supported by the ICE Teaching Innovation Projects (TIC2003) of the Rovira i Virgili University. I would like to thank all those teachers who have given me their support and help.

References [1] [2] [3] [4] [5] [6] [7] [8]

[9]

McMaster University (Canada), http://www.mcmaster.ca/ [May 2005] Case Western Reserve University (United States), http://www.cwru.edu/ [May 2005] Harvard Medical School (United States), http://hms.harvard.edu/hms/home.asp [May 2005] Universiteit Maastricht PBL-site. (The Netherlands), http://www.unimaas.nl/pbl/ [May 2005] Finkle, S.L. y Torp, L.L., “Introductory Documents”, Illinois Math and Science Academy, 1995. http://www2.imsa.edu/programs/pbln/tutorials/intro/intro3.php [May 2005] Savery, J.R. and Duffy, T.M, “Problem Based Learning: An instructional model and its constructivist framework”, Educational Technology 35, 1995, pp. 31-38. “Problem Based Learning”, at Samford University. http://www.samford.edu/pbl/ [May 2005]. “El Aprendizaje Basado en Problemas como técnica didáctica”. Dirección de Investigación y Desarrollo Educativo de la Vicerrectoría Académica del Instituto Tecnológico y de Estudios Superiores de Monterrey http://www.sistema.itesm.mx/va/dide/inf-doc/estrategias/abp.htm [May 2005] Moodle. http://moodle.com/

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