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Students’ perceptions and satisfaction level of hybrid problem-based learning for 16 years in Kyungpook National University School of Medicine, Korea

Purpose: Kyungpook National University School of Medicine has been implementing hybrid problem-based learning (PBL) since 1999. The aim of this study was to investigate the changes in the students’ perceptions and satisfaction levels of hybrid PBL. Methods: The target period of our study was from 1999 to 2014, and target subjects were second-year medical students in Kyungpook National University School of Medicine. The survey was conducted at the end of semester. We had a focused interview with group leaders and some volunteer students. Results: As for the scores regarding students’ overall satisfaction with PBL, there was significant improvement in 2005 compared to 2002, but the scores decreased and no differences between the survey years noted after 2005. The students’ preference ratio for the once a week PBL sessions, tutor presence, synchronization of contents, and arrangement of PBL sessions and related lectures was 60%–80%, 50%–90%, 52%–96%, and 78%–93%, respectively. Conclusion: In order to increase students’ satisfaction with hybrid PBL and to improve the perception of it, firstly, it is necessary to arrange the date and the time of PBL sessions so that students can concentrate on PBL. Secondly, PBL cases should be selected and arranged to be well synchronized with the ongoing lectures. Finally, it is important to create a safe atmosphere so that students can engage actively in PBL sessions.


Introduction
Problem-based Learning (PBL) began to be implemented at some medical schools with innovative curriculum in Asia during the 1970s after Howard Barrows pioneered PBL program at the McMaster University Medical School in the late 1960s [1]. Twenty-three medical schools in Korea have adopted PBL as an experimental or a formal course since the 1990s [2]. The hybrid PBL curriculum of Kyungpook National University School of Medicine (KNUSOM) has been designed to run concurrently with a conventional curriculum over the past decade since it was adopted as a two credits pass/fail course in 1999 [3].

Methods
The questionnaire survey and focused interviews were conducted at the end of the semester. Group leaders and some volunteer students were interviewed using openended questions. The interview was recorded and analyzed with the approval.
The questionnaire was developed using closed-ended items modified from surveys which had been reported in previous studies [3,4,8,12]. The internal reliability of the  inter-year variability.
The differences in students' overall satisfaction levels between years were assessed by one-way analysis of variance after extracting the same five items from the annual PBL questionnaire ( Table 3). The internal relia-  (Table 3, Fig. 1).    On the other hand, many students claimed that they had experienced unsafe atmosphere, difficulty in adjusting to different PBL facilitation skills of tutors due to the insufficient standardization of tutor (Table 4).
7. Students' preference for the grading system:

pass/fail versus grading
The tools for student assessment consisted of tutor assessment, learning report, modified essay questions (MEQs), peer assessment, responding questionnaire, drawing case mapping and schema, and attendance (

Discussion
We define the PBL run concurrently with a lecturebased traditional curriculum as hybrid PBL in this article. The analysis of the changes in the students' perceptions and satisfaction levels of 16-year hybrid PBL showed that students preferred once-a-week PBL to twice or more PBL per week throughout the semester.
This can be interpreted as a way of means for students to choose to lessen the burdens on hybrid PBL at a medical school. Kim et al. [5] also mentioned that when a medical school introduces PBL in a traditional curriculum, it is desirable to impose the least amount of burden on students.
Our results showed that most students preferred the contents of the PBL case to be synchronized with ongoing lectures, and the case to be studied after the related lectures. The possible explanation of preference is that students want to reduce the time and efforts required to study the PBL case and want to be activated the discussion during the PBL session using the knowledge they have learned in previous lectures.
In our study, the students' opinions on the tutor presence were widely distributed (approximately 50%-96%). Students appeared to welcome a tutor who could understand the philosophy and process of the PBL. Park et al. [11] reported that students evaluated the role of tutor as somewhat negative and good facilitation skills of discussion and process of the PBL is strongly required.
Hur & Kim [16] reported that the discussion was often There is no need for tutor in a PBL session if the tutor is too strict. For this reason, investigators claim that tutors need more training to conduct the PBL. These studies support our results of the students' preference for having a tutor and students' perceptions toward tutor.
In our study, the tools for assessment included tutor and peer assessment, learning report, MEQs, responding questionnaire, drawing case mapping and schema, and attendance. Our results revealed that peer assessment proved not to serve as a reliable assessment tool.
According to Kim et al. [18], peer assessment could be used as an effective assessment tool for students' performance in PBL when peer evaluation score is not included in the grades. User-friendly peer evaluation can be used to screen for maladjusted students when students understand the purpose and feedback method of peer assessment well and the questionnaire of peer review is well constituted. Most of the students in our school preferred the pass/fail assessment to grading after consistent with that of Chung et al. [12].
In summary, our results indicate that in order to increase students' satisfaction with hybrid PBL and to improve the perception of it, firstly, it appears to be necessary to arrange the date and the time of PBL sessions so that students can concentrate on PBL.
Secondly, PBL cases should be selected and arranged to be well synchronized with the concurrent lectures.
Finally, it is important to create a safe atmosphere so that students can engage actively in PBL sessions. It is strongly recommended that the tutor should play a role to facilitate the group's thinking and discussion and to guide the PBL process.