The flipped classroom offers a new approach to student-centred teaching and learning by moving the lecture out of the classroom. Research on the topic reveals that the flexibility of viewing the recorded lectures at a time and speed that is convenient to the student is what students appreciate mostly in the flipped classroom. This article examines the viewing pattern of students regarding recorded lectures in a course that has been flipped. The findings reveal a decline in the number of students who view the recordings over the duration of the course semester. Furthermore, the findings support earlier research results revealing that women and older students rely more on recorded lectures than other students. In addition, the study shows that there is a positive correlation between viewing the recorded material and the final grade of students in the course. It is thus surmised that even if in-class activity is very important for the flipped classroom to work, the recordings do have additional value, which is reflected by higher final course grades for students who view them. The flexibility of viewing recordings more than once and at the most relevant and convenient time seems to increase students’ understanding, and is regarded an important asset of flipped classroom teaching.
Flipped learning—also referred to as inverted learning—extends the typical three-hour learning beyond the confines of classroom time through the use of online platforms. In flipped learning, part or all of direct instruction is delivered through videos and other media; and the class time is used for engaging students in collaborative, hands-on activities (Flipped Learning Network, 2014). Many colleges and universities have embraced flipped learning model as it provides opportunities for increased peer interaction and deeper engagement with the material (Johnson, Adams Becker, Estrada & Freeman, 2015). This pedagogical approach has gained such popularity in higher education that 2015 NMC Horizon Report listed flipped learning to be adopted in a large scale in 1 year or less (Johnson et al., 2015). According to a survey conducted by Center for Digital Education and Sonic Foundry, 29% of the higher education faculty in the US reported to be currently implementing flipped learning, and 27% reported to be planning to implement it in near future (Bart, 2013).
Flipped learning appears to be particularly well suited to engineering education because of its potential to “combine learning theories once thought to be incompatible—active, problem-based learning activities founded upon a constructivist ideology and instructional lectures derived from direct instruction methods founded upon behaviorist principles” (Bishop & Verleger, 2013, p. 1). Although engineering educators agree that students learn better when they engage in complex problems and projects (Lombardi & Oblinger, 2007), they are reluctant to forgo lecturing on theoretical and background information necessary for solving engineering problems (Bishop & Verleger, 2013). Flipped learning provides the midway between these two opposite viewpoints and is probably one of the few pedagogical innovations that have received considerable attention and interest (Mitchell, 2014). Despite this increasing interest, there does not seem to be an agreement on what flipped learning is and how effective it is in improving student learning (Sharples et al., 2014). Therefore, it is timely to analyze and synthesize research findings to describe the current state of knowledge and inform future research and development efforts.
Few articles reviewing flipped learning have been published to date (Estes, Ingram, & Liu, 2014; Hamdan, McKnight, McKnight, & Arfstrom, 2013) and only one of them focused specifically on engineering (Bishop & Verleger, 2013). Bishop and Verleger (2013) reviewed 24 studies related to the flipped classroom and concluded that studies mostly focused on student perceptions, which were generally positive and single-group designs. Highlighting the scarcity of studies objectively measuring the impact of flipped approach on student learning, these authors recommended conducting experimental or quasi-experimental studies to investigate objective learning outcomes. Although Bishop and Verleger's (2013) review has provided important considerations for engineering educators, their review is not categorized as a systematic review since their article selection process was not described, and it included studies that were published through the first half of 2012. However, our analyses indicated that approximately 90% of the empirical research on flipped learning was published in 2013 and 2014. Including more recent studies provides a more accurate and up-to-date picture of the current state of flipped learning in engineering education. The following research questions were addressed in this article by following the systematic review steps recommended by Borrego, Foster, and Froyd (2014).
- What are the trends in flipped classroom in engineering education research?
- What kinds of theoretical frameworks and evaluation methods have been adopted in engineering education investigating flipped learning?
- Is flipped learning effective in teaching engineering according to existing engineering education research?
- What are benefits and challenges of flipped learning as reported in engineering education research?
Article selection process
To ensure that relevant studies were located, a wide variety of databases were searched. The keywords searched in all the databases included “flipped” and “engineering” or “flipped” and “engineering education” or “inverted classroom” and “engineering” or “flipped classroom” and “engineering.” Figure 1 displays the complete article selection process based on the inclusion criteria.
As of May 2015, this search yielded 164 results after the duplicates were removed. The articles were organized and tabulated according to context (ie, engineering subdiscipline), and type (eg, empirical, practical, and editorial). The following inclusion criteria were applied: (a) empirical research on the flipped approach in engineering higher education contexts; (b) description of the flipped course design; (c) engineering students and faculty as participants; (d) publication in peer-reviewed journals or conference proceedings. As can be seen in Figure 1, final total of 62 studies were included in the final synthesis. Detailed information about each article is provided as Supporting Information (Table S1).
Several findings emerged as a result of this systematic review of 62 studies on flipped learning in engineering education.
Trends in the flipped learning and engineering education literature
Figure 2 displays the publication trend of proceedings, journal articles and the combined total from 2000 to 2014. Studies published in the first half of 2015—when data collection ended—are included in this review but not reported in Figure 2 since it does not represent an accurate picture of the whole year of 2015. The first article on flipped learning (using the term “inverted learning”) was published in 2003. From then on, research in this area was very limited, with zero to two or three publications a year until 2013. From 2013, flipped learning started sparking more interest amongst engineering education researchers, and 53% of the articles included in this synthesis were published in 2014. In addition, six studies included in this review were published in the first half of 2015 and they were all journal articles. Although conference proceedings outnumber the journal articles, the increasing trend seems to be similar for both of the publication venues. This trend indicates an increase in the number of engineering courses being converted into a flipped format after 2012.
The vast majority of the studies, 66%, were published in conference proceedings, and 34% were published in archival journals (Figure 3). The American Society of Engineering Education (ASEE) is the most common publication venue.
Theoretical frameworks and evaluation methods
This synthesis revealed a paucity of published studies that included a theoretical framework guiding the research and teaching practices. Out of the 62 studies, only 13 referred to a theoretical or conceptual framework. One of the most commonly cited rationales behind converting a course from the traditional to a flipped format was the use of in-class time for active learning exercises rather than for lecturing (Cavalli, Neubert, Mcnally, & Jacklitch-Kuikan, 2014; Velegol, Zappe, & Mahoney, 2015). The other frameworks are listed in Table 1. A detailed description of these theoretical frameworks can be found as Supporting Information (Supporting Material 2).
|Transactional theory||Chen, Wang, Kinshuk, and Chen (2014)|
|The Thayer system||Chetcuti, Hans, and Brent (2014)|
|Problem-based learning & collaborative learning||Chiang and Wang (2015)|
|Cooperative education||Choi (2013)|
|Combination of traditional and constructivist approaches||Davies, Dean, and Ball (2013)|
|Team-based learning||Ghadiri, Qayoumi, Junn, and Hsu (2014)|
|Technology acceptance model||Ivala, Thiart, and Gachago (2013)|
|Revised community of inquiry||Kim, Patrick, Srivastava, and Law (2014)|
|Socio-constructivist theory||Redekopp and Ragusa (2013)|
|Self-directed learning||Rutkowski (2014)|
|Inquiry-based learning||Schmidt (2014)|
Researchers adopted a range of data collection methods to evaluate flipped learning. Quantitative methods involved comparison of exam scores, surveys, course evaluations, institutional data (eg, retention rates) and system log data (eg, time spent on certain activities on a course management system). Use of qualitative data, such as interviews, classroom recordings and observations, was rather limited. A detailed discussion of the evaluation methods adopted in the studies can be found as Supporting Information (Supporting Material 2).
Effectiveness of flipped learning in teaching engineering
Researchers in 30 studies compared student learning in traditional classrooms to learning in flipped classrooms (Table 2). Thirteen studies exclusively reported that students in the flipped classroom outperformed their counterparts in the traditional classrooms. Of these, seven studies reported the statistical significance of their findings. In others, the authors reported an increase in average scores, but did not report a statistical analysis investigating the significance of the observed difference.
|Flipped is more effective||Amresh, Carberry, & Femiani (2013); Chao, Chen, and Chuang (2015); Chiang and Wang (2015)*; Fowler (2014); Kalavally, Chan, and Khoo (2014); Lemley et al. (2013); Mason, Shuman, and Cook (2013b)*; McGivney-Burelle and Xue (2013); Ossman and Warren (2014)*; Papadopoulos and Roman (2010)*; Redekopp and Ragusa (2013); Schmidt (2014)*; Swithenbank and DeNucci (2014); Thomas and Philpot (2012); Yelamarthi, Member, and Drake (2015)*|
|Flipped is more effective and/or no difference||Baepler, Walker, and Driessen (2014); Cavalli et al. (2014); Chetcuti, Hans, & Brent (2014); Choi (2013)|
|No difference||Buechler, Sealy, and Goomey (2014); Davies et al. (2013); Love, Hodge, Grandgenett, and Swift (2014); Mason, Shuman, and Cook (2013b); Olson (2014); Swift and Wilkins (2014); Talbert (2014); Velegol et al. (2015)|
|Flipped is less effective||Hagen and Fratta (2014); McClelland (2013)|
|Flipped is less effective and/or no difference||Lavelle, Stimpson, and Brill (2013)|
Four studies concluded mixed results in terms of learning gain. For example, Baepler et al. (2014) found that students in the flipped section performed significantly higher than the ones in the traditional section during the first year that the flipped approach was implemented, but this difference was not statistically significant in the second year. In nine other studies, researchers did not find any statistically significant difference between flipped and traditional formats in terms of student learning.
Two articles reported that students in the flipped classroom did not perform as well as their counterparts learning in a traditional environment. Hagen and Fratta (2014) observed that even intrinsically motivated students underperformed in the flipped environment. Students had negative perceptions toward the course and felt unprepared for the exams because they had to manage their own learning. Similarly, McClelland (2013) indicated that the average final score for students in the traditional format was significantly higher than the students in the flipped sections. Other researchers, on the other hand, did not find any statistically significant difference between the two formats in terms of exam scores; however, more students failed the course in the flipped section when compared to the average of nonpass in previous years' traditional offerings, and this difference was statistically significant (Lavelle et al., 2013).
To see if there was any difference between student performance in flipped and traditional formats, an analysis of variance was performed based on the mean scores reported in 25 studies. The results indicated that the mean score for flipped was higher than traditional format but this difference was not statistically significant. However, when we controlled for the author as a clustering effect, the difference was statistically significant at the p < .05 level F (1,102) = 4.26, p = .042.
Benefits and challenges of flipped learning
The results of this synthesis indicated that flipped learning provided various benefits and challenges for students and instructors. The benefits can be listed as flexibility, improvement in interaction, professional skills, and student engagement. Challenges included increased workload for faculty, student resistance, lack of opportunities for just-in-time questions, technical issues, decreased interest and neglected material.
One of the most commonly cited benefits of flipped learning was flexibility (Buechler et al., 2014; Kiat & Kwot, 2014; Mok, 2014; Simpson, Evans, Eley, & Stiles, 2003; Velegol et al., 2015). An added value of the flipped approach was being able to rewatch the lecture videos. Students could pause and rewind the videos, take notes and solve example problems while watching the lecture videos. Having access to course materials for 24/7 provided flexibility for students with different learning preferences and personal commitments. This flexible teaching and learning environment also created time for complex problem solving (Ankeny & Krause, 2014; Mok, 2014) and opportunities to cover more materials (Mason, Shuman, & Cook, 2013a, 2013b).
The rationale behind flipped learning is to use face-to-face class time for complex exercises where students can interact with each other and with the instructor. This synthesis concluded that students enjoyed working with their peers (Bailey & Smith, 2013; Ghadiri et al., 2014; Love et al., 2014; Talbert & Valley, 2012) and having the instructor available for help (Clark, Norman, & Besterfield-Sacre, 2014; Lemley et al., 2013; McGivney-Burelle & Xue, 2013; Mok, 2014; Swithenbank & DeNucci, 2014).
Student-centered instructional approaches, like flipped learning, not only help students learn the content but also provide opportunities to improve professional skills that “today's competitive global market and changing work environment demand engineers to possess” (Kumar & Hsiao, 2007, p. 18). Several authors argued that flipped learning contributed to students' professional skills such as life-long learning (Luster-Teasley, Hargrove-Leak, & Waters, 2014), learner autonomy (Kim, Kim, Khera, & Getman, 2014; Mok, 2014), critical thinking (Chetcuti et al., 2014) and interpersonal skills (Yelamarthi et al., 2015).
Another benefit that this synthesis revealed was student engagement (Lavelle et al., 2013). Several researchers found that students came to class better prepared (Chetcuti et al., 2014; Jungic, Kaur, Mulholland, & Xin, 2015; Mok, 2014; Papadopoulos & Roman, 2010), and they devoted more time and formed better study habits compared to traditional classroom approaches (Papadopoulos & Roman, 2010).
Although the findings in terms of class attendance varied, some researchers found that the flipped format increased attendance (Chen et al., 2014; Rutkowski, 2014) and retention rate (Kim, Patrick, et al., 2014; Love et al., 2014). For example, Rutkowski (2014) found that regular lecture attendance increased from 55% to 70% when the course was converted to the flipped format. Similarly, Chen et al. (2014) found out that students logged into the course platform more frequently to access course materials compared to the prior versions of the course.
Challenges of flipped learning
As with any new approach, flipped learning brings some challenges for instructors and students. The biggest challenge for instructors was the heavy workload prior to and during class. Converting a course from a traditional teaching approach to a flipped format required a reasonable amount of front-end investment from faculty members (Ghadiri et al., 2014; Kalavally et al., 2014). During class, on the other hand, one instructor had to serve many students requesting assistance (Clark et al., 2014).
Challenges for students included uninteresting online material, technical issues and insufficient knowledge about the new approach. For example, students in Amresh, Carberry, and Femiani's (2013) study found the online videos boring. Similarly, the length of the videos contributed to lack of interest in the material (Olson, 2014). Other researchers found that students could easily skip some of the materials in the flipped classrooms. For example, Ossman and Warren indicated that rather than watching the videos, students read the slides (2014). Velegol and her colleagues made the lecture attendance optional, so students who were able to finish their homework on their own chose not to attend the class (2015).
Although it is generally accepted that today's net generation students ubiquitously use various technological tools and applications in their daily lives, this synthesis implied that technical issues frustrated students (Clemens et al., 2013; Tague & Baker, 2014). Students complained about the connectivity speed which is assumed to have been resolved at least on higher education campuses (Everett, Morgan, Stanzione, & Mallouk, 2014).
Student resistance was another challenge that flipped learning instructors faced. Having gone through a traditional approach throughout their educational career, students felt overwhelmed when faced with a new approach that required them to actively participate in the learning process (Amresh et al., 2013; Bland, 2006; Gannod, Burge, & Helmick, 2008). Students who lacked metacognitive and organizational skills struggled in flipped classrooms (Margoniner, 2014) as they opined that they were not being taught; rather, they taught themselves (Talbert & Valley, 2012)
Trends in the flipped learning and engineering education literature
The publication trend indicates that there is a proliferating interest in flipped learning in engineering education. Benefits such as learning gain, flexibility, opportunities for interaction and student engagement seem to have encouraged several engineering educators to convert their traditional classrooms to a flipped format. However, the scarcity of archived journal publications indicates that research on flipped learning in engineering education is still in its infancy. The conference proceedings usually adopted a practice-oriented approach; and focused on documenting the design and development process and sharing some preliminary findings and student feedback. Further systematic research investigating different components and claims of flipped learning using various research methods is needed to establish flipped learning as an effective pedagogical approach in the field.
Theoretical frameworks and evaluation methods
As a critical component of disciplined research, theoretical frameworks help researchers to organize and create a strong argument to justify the significance of a given research problem and guide selection of appropriate data collection and analysis methods (Antonenko, 2015). More than 50% of the studies included in this review lacked a theoretical framework for implementing flipped learning in engineering education. If flipped learning has the potential to combine learning theories once thought to be incompatible, as Bishop and Verleger (2013) argued, then the research on flipped learning needs to detail how this combination can be successfully implemented with the aid of varied instructional technology tools. These models need to present strategies for engineering educators for designing, developing and evaluating instruction.
The most commonly cited motivation behind converting a course from the traditional to a flipped format was the use of in-class time for active learning exercises rather than for lecturing. However, active learning itself is an ambiguous term that has been used and interpreted differently by various researchers and practitioners (Prince, 2004). A multitude of activities ranging from pausing the lecture for a few minutes and asking students to compare notes with each other to simulations and games would fall under the category of active learning. Some of these activities do not necessarily require flipping the instruction. Therefore, specific pedagogical models that may fall under the umbrella of the term “active learning” such as case-based reasoning, problem-based learning and project-based learning could provide a clearer direction for researchers and practitioners.
Evaluation methods were limited to grade comparisons to measure learning gain and surveys to get student feedback. These methods provide valuable information about the role of flipped approach in student learning; however, they may fall short in analyzing the overall impact. Bishop and Verleger (2013) called for more experimental studies to investigate the effectiveness of the flipped approach, but this review indicated that more systematic qualitative and mixed-method approaches are needed to understand what flipped learning entails and how it supports student learning in various ways.
Effectiveness of the flipped learning
The results of this systematic review indicated that flipped learning was more effective than traditional lecture method in many cases. It would have been ideal to conduct a meta-analysis to make a definitive conclusion about the superiority of flipped approach over traditional approach; however, majority of the studies included in this study failed to report mean scores, standard deviations and number of observations required for a meta-analysis. The studies also used different measurements (eg, final course grades, exam scores, quiz scores) which made such a comparison difficult. However, one-way ANOVA test results based on the studies that reported a mean score indicated that students in the flipped approach learned the content as much as their counterparts in the traditional approach if not better.
Benefits and challenges of flipped learning
Flipped learning approach seemed to be promising in regards to the benefits it provides for students and instructors. Yet, the research focused on measuring the effectiveness of the new approach through comparisons to traditional approaches, and the conclusions about benefits were reported as additional findings. Therefore, further research is needed to investigate the transferability of these findings to different contexts. Specifically, the claims about the professional skills and increased interaction need to be investigated thoroughly. For example, only one study included in this review analyzed how students interacted with each other during face-to-face problem sessions and learned how their conversations shifted from simply recalling facts to conceptual discussions (Lin et al., 2014). Further research investigating the student engagement and interaction in the face-to-face sessions would help instructors who have hesitations about individual contributions in collaborative group assignments. This line of research can also produce a list of guidelines for successfully flipping an engineering course and help practitioners to identify areas of problems and develop interventions as needed.
Some of the challenges cited in these studies, such as heavy workload and technical issues, can be addressed effectively. Instructors might be advised to gradually convert their courses rather than doing it all at once because material development might be overwhelming. Although it may not be plausible to foresee every technical issue, making students aware of possible issues might reduce frustration. Some other challenges, on the other hand, raise some crucial concerns about the design of a flipped classroom. Studies that found a lack of engagement in the flipped format seemed not to make full use of the format (eg, Ossman & Warren, 2014; Velegol et al., 2015). Online materials need to be carefully designed and complex problems, where students are required to collaborate and interact with each other and the instructor, should be assigned for in-class sessions. This would increase lecture attendance and engagement as concluded in studies by Chen et al. (2014) and Rutkowski (2014).
Recommendations for future research and practice
The findings of this systematic review serves as the basis for recommendations for engineering educators who plan to investigate the role of flipped learning in engineering education.
Reforming engineering education through theoretically sound frameworks
Engineering education research needs to focus more on what specific aspects of active learning might be complemented in a flipped format and how that could help form engineers for today's competitive global market and changing work environment. Researchers need to make informed decisions about which theoretical framework would provide a structure to systematically study the role and impact of the flipped approach in engineering education.
Using qualitative and longitudinal data to provide deeper understanding
This synthesis reveals that there is a paucity of literature employing qualitative methodologies that would provide more in-depth understanding of learning in a flipped environment. Additionally, there is a lack of longitudinal studies investigating the student experiences over a long period of time. Rather, studies were mostly conducted over a semester when the new approach is implemented for the first time. It is very likely that an innovation will be successful because of its novelty, or will fail because of insufficient experience. Therefore, this synthesis calls for longitudinal studies investigating student experience over a longer period of time which may even involve postgraduation.
Investigating systematic adoption of flipped learning in engineering education
A vast majority of the studies included in this review examined flipped learning in specific courses rather than at the program or discipline level. Although the decision on how to teach is at the discretion of individual instructors, higher education institutions encourage and sometimes require, faculty members to adopt innovative pedagogical approaches like flipped and blended learning (Sheppard, 2013). Studying the phenomena of flipped learning at broader levels (ie, program, discipline) may help engineering educators understand the overall impact of the pedagogy and how it might influence student readiness for a new teaching approach. It would also help practitioners to adopt strategies to address student resistance when they implement a new teaching technique.
Shifting the focus from academic skills to professional skills
This synthesis reveals that researchers generally focus on students' academic gains when they adopt a new pedagogical approach. Although it is an important component of learning, report of academic achievement or failure only provides partial information about the role of innovative pedagogies in teaching engineering skills. Very few researchers argued that flipped learning improved students' professional skills such as life-long learning, self-regulation, inter-personal communication. Further research is needed to systematically investigate whether or not flipped learning enhances these skills. Developing measures and alternative assessments, of which the development process is clearly described, and the reliability and validity analyses reported, will considerably contribute to the research in the field.
This systematic review of research on flipped learning in engineering education is timely as the flipped approach has gained popularity amongst engineering educators. It is imperative to understand the current practices in order to shed light on future implementations. The review of 62 articles included in this synthesis was framed around four major research questions. First, the findings indicated a widespread adoption of flipped learning in various sub-fields of engineering. Second, there is a paucity of the report of theoretical frameworks guiding the development and evaluation of the flipped approach. Evaluation methods have mostly been limited to quantitative data drawn from course assessments and surveys, and there is a scarcity in qualitative research to understand phenomena in depth and within specific contexts. Third, many researchers found that students in the flipped classroom had learned as much as their counterparts in the traditional lecture-style format if not more. Fourth, flipped learning provides several benefits and brings some challenges for instructors and students. Synthesizing the existing research on flipped learning, this study provides recommendations for researchers, practitioners and policy-makers to develop research-based action plans in how to develop and evaluate flipped classrooms.
Statements on open data, ethics and conflict of interest
We declare that the data will be available by individual application directly to the first author. We declare that no human participants used in this study. We declare that we do not have any conflicts of interest regarding the reported study.
Aliye Karabulut-Ilgu is a lecturer in the Department of Civil, Construction and Environmental Engineering at Iowa State University.
Nadia Jaramillo Cherrez is a doctoral student in School of Education at Iowa State University.
Charles T. Jahren is the W. A. Klinger Teaching Professor in the Department of Civil, Construction and Environmental Engineering at Iowa State University.
What is already known about this topic
- Flipped learning has gained popularity in higher education.
- Flipped learning has been used in a wide range of engineering subdisciplines.
- Flipped learning creates opportunities for complex problem solving in engineering education.
What this paper adds
- There is a paucity of reporting regarding theoretical or conceptual frameworks guiding the development and evaluation of the flipped approach.
- Evaluation methods have mostly been limited to quantitative data drawn from course assessments and surveys, and there is a scarcity in qualitative research.
- Students involved in the flipped approach have learned as much as their counterparts in the traditional lecture-style format if not more.
Implications for practice and/or policy
- Flipped learning course design and research need to be based on a theoretical framework.
- Flipped learning research needs to employ quantitative and qualitative methods to understand the phenomena in depth.
- Further systematic research addressing validity and reliability concerns is needed to consolidate the role of flipped learning in enhancing student learning.