Study setting and population
The second-year undergraduate nursing students at the Nursing School of Fujian Medical University (Fuzhou, China) formed the study population. The students were randomly assigned by a computer into two classes (classes 1 and 2) upon entry to the university, with 164 and 131 students in class 1 and class 2, respectively. Thus, randomization in this study occurred at the class level. An administrator employed by the university, who had no information regarding the recruitment or data collection, was invited to conduct the random allocation. Two labels (numbered 1 and 2) were placed in opaque envelopes, and the administrator subsequently requested the Medical Nursing teacher to draw one envelope at random. If “number 1” was picked, class 1 was to be the experimental group; otherwise, class 2 was to be the experimental group. As “number 1” was selected, there were 164 students in the experimental group and 131 in the control group at the beginning of the study. The experimental group involved eight subgroups, while the control group involved seven subgroups, with each subgroup consisting of approximately 20 students.
The general characteristics were compared between the two classes and there were no significant differences (Table 1). However, there were significant differences between the control and experimental groups in academic performance regarding all seven Professional Basic courses of the previous academic year (p<0.05) (Table 2).
Teaching approaches
The Medical Nursing course was conducted over 1 academic year (two semesters), with 144 teaching hours in both the experimental and control groups. The same teacher, textbook, and additional resources were provided to both groups. An additional file shows the teaching arrangement in both groups in more detail [Additional file 1: Table S1]. The experimental group underwent blended learning, whereas the control group underwent offline case-centered learning. Although blinding of the students and teachers was not possible, the data analyst was blinded.
Experimental group
Teaching arrangement
The teaching arrangement in the experimental group is presented in Supplementary Table 2. The experimental group received blended learning, which combined online learning with offline flipped classrooms. The teacher prepared the content prior to each offline flipped classroom (Figure 1).
Figure 1 Tasks of the teacher prior to each offline flipped classroom
Offline flipped classrooms
All students had access to the chaoxing platform (http://i.mooc.chaoxing.com/space/index.shtml), where they watched the pre-recorded lecture videos and accessed the online quizzes, forums, and study materials. Students were required to watch the lecture videos, and subsequently divided into groups (approximately five students per group) to discuss the case and the question that the teacher provided prior to the class. In addition, they recorded their discussion, produced a report, and handed in the recording and report after the discussion. Questions could be asked in the online forums during the learning process (Figure 2).
Each offline flipped classroom involved approximately 20 students, and they were divided into four groups (approximately five students per group) based on the pre-class group discussions. To assess the students’ mastery of the lesson prior to class, online quizzes, which lasted approximately 10 min, were performed at the beginning of the flipped classroom. Subsequently, the teacher provided detailed explanations of the quiz questions according to the results, and the students reported what they had discussed prior to class. After each group completed the reporting, other groups asked questions or provided supplementary answers. The teacher commented on each report and summarized the results of the group discussions. Additionally, the teacher pointed out the problems that the students needed to pay attention to in their study, and guided the students to think and discuss according to the discussions and feedback. Towards the end of the class, the teacher guided the students to review and summarize the important knowledge points of the lesson. After each class, the students were requested to submit homework to the platform, raise questions in online forums or review teaching videos (Figure 2). All study data were recorded via the platform and could be accessed by the teacher.
Figure 2 Blended learning in the experimental group
Control group
Teaching arrangement
All learning resources were identical in the experimental group, except the absence of pre-recorded lecture videos for the control group.
Traditional case-centered seminars
The control group received offline case-centered learning via seminars throughout the two semesters. Each seminar involved approximately 20 students. In class, students formed small groups to discuss the cases under the guidance of the teacher. Subsequently, the teacher randomly selected groups to answer questions. Comments and explanations were provided by the teacher according to the answers. Additionally, the teacher guided the students to think, discuss, and summarize the knowledge points of the class. When class was almost over, quizzes were conducted to monitor the students’ mastery of the lesson. After class, the students were required to summarize the key knowledge points and submit the summary.
Evaluation of learning outcome
Academic performance
Both the experimental and control groups underwent the same final exam, quizzes, and homework. The maximum total score for the course was 100. The total score was determined using the following weights:
(1) Experimental group: final exam, 50%; quiz, 20%; online learning progress requirements, 15%; discussion, 10%; and homework, 5%.
(2) Control group: final exam, 50%; quiz, 20%; course notes, 15%; discussion, 10%; and homework, 5%.
Assessment of the critical thinking ability of students
Numerous tools, such as the California Critical Thinking Disposition Inventory (CCTDI) [27] and the California Critical Thinking Skill Test [28], have been designed to measure critical thinking in nursing. The CCTDI has been specifically developed and used for nursing students [29]. It has been shown to be a valid instrument for assessing critical thinking ability among nursing students in different cultural contexts [30]. The population included in the present study consisted of Chinese students. Hence, the California CTDI-Chinese Version (CTDI-CV), which was translated, modified, and validated by Chinese researchers, was more suitable than the original [31]. The CTDI-CV exhibits a good overall content validity index (0.89) and Cronbach’s alpha (0.90), indicating satisfactory content validity and internal consistency, respectively [31].
The CCTDI measures overall critical thinking disposition. It consists of seven subscales that measure the following dispositions: truth-seeking, open-mindedness, analyticity, systematicity, critical thinking self-confidence, inquisitiveness, and cognitive maturity. Potential scores range from 5 to 60 for each subscale, with a maximum total score of 420. The students in the two classes completed the questionnaire prior to and following the teaching experiment.
Statistical analysis
All statistical analyses were conducted using the IBM Statistical Package for the Social Sciences (SPSS), Version 22.0 (IBM Corp., Armonk, NY, USA). Mean and standard deviation were used to represent the normally distributed continuous data, while median (M) and quartiles (P25, P75) were used to represent the non-normally distributed continuous data. If the continuous variables were normally distributed and exhibited homogeneity of variance, the t-test was used to assess the difference in learning outcomes between the two groups. Otherwise, the nonparametric rank-sum test was used. The chi-squared test was used to compare the baseline characteristics (regarding categorical variables) between the two groups. The significance level was set at 0.05.