Visual analysis of blended learning research
From 2000 to 2021 (retrieval date: December 2021), there were 1537 valid papers, including 1472 research papers and 65 review papers. As shown in Fig. 1, the research can be divided into three stages: from 2000 to 2005, there were few research papers published, with an average annual number of 5; the number of research articles published from 2006 to 2014 showed an upward trend; the third stage was a period of rapid development from 2015 to 2021, with more than 100 research articles published each year.
The essence of education is the transmission of knowledge, which is closely associated with the Internet for information accumulation, transmission and commutation [23]. In July 2015, the State Council issued the Guidance Opinions on Actively Promoting ‘internet plus’ Action, and more schools began to focus on the expansion of educational resources and educational service platforms, with the purpose of implementing a new networked blended-learning mode [24]. This has resulted in the rapid development of blended learning-related research since 2015. To date, blended learning remains a hot topic of research in the education field.
Fig. 2 depicts the keywords co-occurrence network in the field of blended learning research. There are 341 nodes, 957 connected lines, and a network density of 0.0165. Each node represents a keyword, and the node size is in direct proportion to its frequency. The darker the center color of the node is, the higher the centrality is assigned, and the higher the value is, the more central the keyword is in the whole network. Hot keywords in the field of blended learning model research are: the first category is theoretical and technical keywords, including education, online, skill, technology, etc., the second category is the key words of practical application, including curriculum, performance, perception, Instruction, satisfaction, etc.
This study analyzed burst keywords with CiteSpace to discover the cutting-edge terms in the field of blended learning. The Burst keywords map of blended learning research is shown in Fig.3. The strength of the burst keywords represents the degree of attention received by researchers, and the graph can also reflect the time when the node appeared, the time when the burst began, the time when the burst ended, and the time period of the burst, so as to analyze the development process of the frontier hot spots of blended learning.
The top 10 burst keywords were, in order, engagement (5.45), flipped classroom (4.68), technology (4.59), web (3.98), ict (3.93), feedback (3.91), and instruction (3.56), anatomy(3.56), clinical education(3.38), which indicates that the integrated application of web-based curriculum and flipped classroom mode and other teaching methods have received strong attention, as well as the blended learning has been carried out more widely in the field of medical education.
Web, feedback, communication and other words stand out for a long time, whereas engagement, flipped classroom, achievement, course and other words came to light recently. This showed that while the teaching practice and network platform construction of blending learning are developing, the research on the origin of education, such as educational technology and teaching effect, has also received attention in recent years.
The search results
A total of 1135 articles were obtained through literature retrieval. After eliminating duplicate and irrelevant articles, the remaining 52 articles were screened according to inclusion and exclusion criteria, and a total of 21 articles[25-45] meeting the requirements were obtained.
Characteristics of included studies
Among the included articles, twenty articles [26–45] reported the difference of theoretical scores between the experimental group and the control group, six articles [25, 27, 31, 41, 42, 45] reported the difference of experimental operation scores, two articles [27, 29] reported the differences in various learning abilities such as autonomous learning ability. The sample sizes ranged from 56 to 373 participants and the pooled sample size was 3527(experimental group = 1621, control group = 1906). All study outcomes were measured using theoretical scores, experimental operation scores or questionnaire surveys. Table 1 shows the characteristics of the 21 included studies. Table 2 shows the risk of bias assessment of the 21 included studies.
Effects of interventions on theoretical scores
Twenty-one studies [25–45] compared the effects of BL and conventional teaching method on theoretical scores of pharmacy students. A total of 3390 samples were included in the meta-analysis, including 1553 in the experimental group and 1837 in the control group. There was statistical heterogeneity among the studies (P < 0. 00001, I2=93%), and a random-effect model was used for meta-analysis. Mean difference (MD) is the difference between the mean of test group and the mean of control group. The results showed that the theoretical scores of students in the experimental group were better than those in the control group (MD=6.10, 95%CI[4.46, 7.75], P < 0.00001)(Fig. 4).
Due to the heterogeneity among studies of theoretical scores, sensitivity analysis was performed to verify the reliability of the results. After excluding six studies [25, 27, 31, 41, 42, 45], the pooled effect size favored the blended learning group (MD = 5.37, 95 %CI [4.16, 6.58], P < 0.00001).The effects observed in the primary analysis did not change.
The funnel plot of the 21 theoretical score analysis showed an obvious asymmetry, demonstrating possible publication bias(Fig. 5)
Table 1 The characteristics of the 21 included studies
Study ID
|
Published year
|
Teaching level
|
disciplines
|
Sample size
(T/C)
|
Interventions
|
Comparator teaching approach
|
outcome indicator
|
Zheng & Zhang [25]
|
2020
|
Higher vocational
|
Comprehensive pharmacy training
|
68/69
|
B-Learning
|
Conventional teaching
|
②
|
Jiang & Ning [26]
|
2020
|
Undergraduate
|
Molecular biology
|
40/47
|
B-Learning
|
Conventional teaching
|
①
|
Zhang[27]
|
2020
|
Higher vocational
|
Pharmaceutics
|
40/38
|
B-Learning
|
Conventional teaching
|
①②③
|
Liu et al. [28]
|
2017
|
Undergraduate
|
Clinical pharmacy
|
72/72
|
B-Learning
|
Conventional teaching
|
①
|
Wu et al. [29]
|
2020
|
Junior College
|
Human anatomy and physiology
|
100/100
|
B-Learning
|
Conventional teaching
|
①③
|
Zhong& Cao[30]
|
2020
|
Undergraduate
|
Pharmacology
|
201/164
|
B-Learning
|
Conventional teaching
|
①
|
Lin et al. [31]
|
2018
|
Junior College
|
Pharmaceutics
|
111/119
|
B-Learning
|
Conventional teaching
|
①②
|
Zhang et al. [32]
|
2020
|
Undergraduate
|
Natural pharmaceutical chemistry
|
130/160
|
B-Learning
|
Conventional teaching
|
①
|
Zhang et al. [33]
|
2020
|
Undergraduate
|
Human histology
|
42/40
|
B-Learning
|
Conventional teaching
|
①
|
Zhou et al. [34]
|
2019
|
Undergraduate
|
Integrated pharmaceutical knowledge and skills
|
28/28
|
B-Learning
|
Conventional teaching
|
①
|
Chen[35]
|
2021
|
Undergraduate
|
Pharmacology
|
49/48
|
B-Learning
|
Conventional teaching
|
①
|
Xiong et al. [36]
|
2018
|
Higher vocational
|
GMP practice and safety in production
|
31/36
|
B-Learning
|
Conventional teaching
|
①
|
Xing et al. [37]
|
2021
|
Undergraduate
|
Pharmacology
|
86/93
|
B-Learning
|
Conventional teaching
|
①
|
Sui et al. [38]
|
2020
|
Undergraduate
|
Analytical chemistry
|
58/152
|
B-Learning
|
Conventional teaching
|
①
|
Jia et al. [39]
|
2021
|
Undergraduate
|
Physiology
|
18/38
|
B-Learning
|
Conventional teaching
|
①
|
Sun et al. [40]
|
2020
|
Undergraduate
|
Medicinal chemistry
|
41/138
|
B-Learning
|
Conventional teaching
|
①
|
Wang et al. [41]
|
2021
|
Undergraduate
|
Inorganic chemistry
|
188/185
|
B-Learning
|
Conventional teaching
|
①②
|
Li et al. [42]
|
2021
|
Undergraduate
|
Biopharmaceutical and pharmacokinetic experiments
|
141/203
|
B-Learning
|
Conventional teaching
|
①②
|
Gao [43]
|
2019
|
Junior College
|
Traditional Chinese medicine outline
|
58/56
|
B-Learning
|
Conventional teaching
|
①
|
Cai et al. [44]
|
2021
|
Undergraduate
|
Anatomical physiology
|
90/92
|
B-Learning
|
Conventional teaching
|
①
|
Cai et al. [45]
|
2016
|
Undergraduate
|
Histoembryology
|
29/28
|
B-Learning
|
Conventional teaching
|
①②
|
T experimental group,C control group,① theoretical scores,② experimental operation scores,③ questionnaire
Table 2 Risk of bias assessment of the 21 included randomized controlled studies
Study ID
|
Published year
|
Randomization
|
Allocation
concealment
|
Blinding
|
Incomplete data report
|
Selective data report
|
Other bias
|
Zheng & Zhang [25]
|
2020
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Jiang & Ning [26]
|
2020
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Zhang[27]
|
2020
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Liu et al. [28]
|
2017
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Wu et al. [29]
|
2020
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Zhong& Cao[30]
|
2020
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Lin et al. [31]
|
2018
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Zhang et al. [32]
|
2020
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Zhang et al. [33]
|
2020
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Zhou et al. [34]
|
2019
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Chen[35]
|
2021
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Xiong et al. [36]
|
2018
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Xing et al. [37]
|
2021
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Sui et al. [38]
|
2020
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Jia et al. [39]
|
2021
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Sun et al. [40]
|
2020
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Wang et al. [41]
|
2021
|
Yes
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Li et al. [42]
|
2021
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Gao [43]
|
2019
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Cai et al. [44]
|
2021
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Cai et al. [45]
|
2016
|
Unclear
|
Unclear
|
Unclear
|
None
|
None
|
None
|
Effects of interventions on experimental operation scores
There were six studies [25,27,31,41,42,45] that used experimental operation scores as an evaluation index for the comparison between BL and conventional teaching method, with a cumulative sample size of 1219 cases, including 577 cases in experimental group and 642 cases in control group. The results showed statistical heterogeneity among studies (P < 0.00001, I2= 99%), so the random-effect model was used for meta-analysis. The experimental operation scores of the experimental group was better than that of the control group [MD=6.50, 95%CI (4.33, 8.67), P < 0.00001](Fig.6). The combined effect size did not change significantly after the single studies were removed one by one, indicating that the results of meta-analysis were relatively stable.
Effects of interventions assessed by questionnaires
Two studies [27, 29] set autonomous learning ability, knowledge application ability and teamwork awareness as evaluation indicators for the comparison between BL and conventional teaching method. The cumulative sample size was 278 cases, including 140 cases in the experimental group and 138 cases in the control group. Relative risk (RR) is essentially the rate ratio or risk ratio, which reflects the strength of the association with exposure. According to the results, the experimental group was superior to the control group in the above aspects, with statistical significance (P < 0.05)(Table 3).
Table 3 Meta-analysis of questionnaire survey results
questionnaire items
|
literature quantity
|
fixed effect model
|
random effects model
|
RR(95%CI)
|
P
|
RR(95%CI)
|
P
|
Autonomous learning ability
|
2
|
1.29(1.14~1.46)
|
<0.0001
|
1.29(1.14~1.46)
|
<0.0001
|
Knowledge application ability
|
2
|
1.22(1.09~1.36)
|
0.0007
|
1.22(1.09~1.36)
|
0.0007
|
Teamwork awareness
|
2
|
1.21(1.09~1.33)
|
0.0002
|
1.20(1.09~1.32)
|
0.0002
|
Interpersonal communication ability
|
2
|
1.27(1.11~1.45)
|
0.0005
|
1.27(1.11~1.45)
|
0.0004
|