Sustainable Effect of the Usefulness of and Preference for Digital Textbooks on Perceived Achievements in Elementary Education Environments

Abstract

This empirical study was conducted to evaluate whether digital textbooks contribute to sustainable development in school education. Accordingly, 690 students participated in the three-year research, and the data on the relationship between students’ perceived usefulness/preference for digital textbooks and academic achievement were analyzed using latent growth curve model statistics. The results showed that the usefulness of and preference for digital textbooks had a significant effect on academic achievement, with the impact enhancing depending on the increase in their preference. To cope with new digitalized education settings, especially in the post-COVID-19 era, digital textbooks should be flexible, connected, instructional, and data driven so that schools can achieve sustainable development.

1. Introduction

The outbreak of COVID-19 has triggered a digital revolution, changing the paradigm of school education [1]. Online education is not a temporary education system adopted for the duration of the COVID-19 crisis but could evolve into a general education system even after the pandemic ends. In the business area, as changes in job types triggered by telecommuting are gaining increasing acceptance, distance education using digital content would also be further activated. Classes on video-conferencing tools such as “WebEx”, “Zoom”, and “Google Meet”, using various educational applications, are already being actively conducted. Accordingly, it is predicted that the existing educational settings with printed textbooks will also switch to the use of digital textbooks for the facilitation of sustainable education of the future [1].

Digital textbooks or e-books serve as the text for learning in schools [2]. They may be used as text not only for traditional in-person classes, but also for online courses.

The features applied to digital textbooks are becoming sophisticated with the development of technology. In particular, immersive content has been included in digital textbooks, supporting vivid learning experiences by offering three-dimensional audiovisual effects [3]. This supports an in-depth understanding of learning and experience-oriented activities by observing and directly manipulating objects and spaces. Specifically, recent technologies, such as virtual reality and augmented reality, are being applied. More high-tech classes will be made possible by applying advanced technologies to learning activities [4].

In this respect, the current world situation related to COVID-19 has a direct impact on instructional methods, requiring the next level of education, such as remote and online education. These would include various types of digital resources, and we need to prepare for effective support to enhance new learning environments. The contribution of information and communication technology (ICT) is crucial to overcome these challenges and achieve the continuity of education [5].

Many countries have introduced policies and conducted studies related to the digitalization of textbooks. Specifically, the issuance and utilization of digital textbooks and educational effectiveness have been verified, and research has focused on whether digital textbooks help students improve their competency. However, since most of these studies cover a short period, there is limited evidence to systematically judge whether digital textbooks could be used consistently in schools. To determine whether innovative education, including digital textbooks, can be applied to education, it is essential to have empirical research results over a longer period of utilization.

Therefore, this study was conducted to contribute to ensuring educational sustainability during and after the COVID-19 era by verifying the longitudinal effectiveness of digital textbooks. The purpose of this longitudinal study is to verify sustainable achievements on the usefulness of and preference for digital textbooks. Accordingly, the research hypotheses are as follows:

Hypothesis 1 (H1).

The usefulness of and preference for digital textbooks perceived by students will affect the sustainable improvement of achievement in social studies classes.

Hypothesis 2 (H2).

The usefulness of and preference for digital textbooks perceived by students will affect the sustainable improvement of achievement in science classes.

2. Background

2.1. Digital Textbooks and Education

Digital textbooks are light digital devices—such as laptops or tablets—that combine Internet connectivity, interactive and personalized content, learning videos and games, and other creative applications to enable collaboration with other students, while providing instantaneous feedback to the student and teacher [6]. Digital textbooks, which are expected to revolutionize teaching, are not simply a digital form of static printed textbooks. They include abundant learning materials and learning management systems in addition to the existing curriculum to support terminology dictionaries, multimedia dictionaries, immersive content, and evaluation tools. They can also link external data on educational infrastructure [1] (p. 6).

Some countries, such as Australia, Canada, China, Finland, France, Malaysia, the Netherlands, Singapore, Sweden, the United Kingdom, the United States, and Vietnam, have used digital textbooks, e-books, or online learning content in K-12 schools [4]. For example, the United States government announced the ConnectED initiative, which aimed to empower teachers with the best technology and students with individualized learning and rich digital content [7]. The Federal Communications Commission emphasized the importance of the Digital Textbook Playbook to help K–12 educators and administrators begin building rich digital learning experiences for students, after the Playbook was first published in 2012 [8]. Meanwhile, the strategic approaches to digital education across Europe are focused on the development of digital competence through school curricula, teacher-specific digital competences, assessment of students’ digital competences, and the use of technology in assessment and testing [9]. The federal government of Canada declared the Digital Canada 150 policy in 2014 and specified that digitalization in education should be practiced as a provincial responsibility [10]. In response, the province of British Columbia has been providing e-textbooks and online courses for students and educators on the Open School BC platform [11].

2.2. Contextual Use of Digital Textbooks

In Korea, policies have been drafted to develop digital textbooks into a comprehensive educational service platform beyond electronic textbooks [3]. A prototype of digital textbooks was developed in 2008, while related laws and systems were established in 2012. Digital textbooks have begun to be applied through the operation of professional development schools since 2014. Starting from 2018, schools officially started introducing digital textbooks gradually. Specific plans of the digital textbook in K–12 schools are as shown in

Table 1. Annual application plan for digital textbooks [12].

Index	Grade	Subject	Year
			2018	2019	2020
Elementary school	3–4	Social studies, Science, English
	5–6	Social studies, Science, English
Middle school	7	Social studies, Science, English
	8	Social studies, Science, English
	9	Social studies, Science, English
High school	10	English

below.

Elementary schools use digital textbooks for social studies, science, and English subjects from Grades 3–6. Grades 3 and 4 have started using digital textbooks since 2018, and Grades 5 and 6 since 2019. Middle schools have used digital textbooks in the same subjects applied in elementary schools in Grades 7–9 since 2018, 2019, and 2020, respectively. Digital textbooks have been used for English since 2018 for high schools.

As demonstrated in Figure 1, there are several useful features of digital textbooks that help students enhance learning effectiveness, such as the following:

• Bookmarks: Use bookmarks on important pages;
• Highlight: Mark the selected content with a highlighter;
• Memo: Write a memo in the selected area;
• Recording: Record in the selected area with the block;
• Hyperlink: Connect URLs or files to the selected area with the block;
• External resources: Search terminology using external links;
• Copy: Copy the selected area with the block;
• Virtual reality: Install and run virtual reality content;
• Augmented reality: Install and run augmented reality content;
• 360° Picture/Video: Execute photos/videos taken in 360 degrees;
• Textbooks: Move to the downloaded digital textbook list;
• Index: Check and move digital textbooks and content;
• My box: View the list of memos, recordings, hyperlinks, and copies added to the digital textbooks;
• Note: Write one’s own notebook by adding text and images to learning content;
• Write: Write or draw pictures on the digital textbook content;
• Search: Search for the content in the digital textbook or in external resources;
• Communities: Move to learning communities;
• Material sharing: Sharing learning materials and files between users;
• Screenshot: Capture and export digital textbook screen or save as image file.

As long as there is Internet connectivity, every student can easily access the digital textbook and use it. Therefore, digital textbooks are expected to be increasingly used in the future, and their roles are expected to be as follows [1]. First, they would develop students’ digital competency, contributing to bridging the digital divide. Since qualified digital literacy would be necessary to use digital textbooks in schools, the widespread use of digital textbooks implies that students’ digital competency would be enhanced. Second, they can be differentiated from printed textbooks, owing to the provision of various multimedia materials and learning functions of digital textbooks. Digital textbooks are not just electronic transcriptions of the contents of printed books, but tools to support learning by applying a wide range of effective technologies. Third, learning activities conducted through digital textbooks will be stored as systematic data. The collected data, when delivered to teachers and students after analysis, will contribute to the improvement of educational activities. Based on this learning analytics, individualized learning can be implemented.

2.3. Digital Textbooks and Their Learning Effects

Experimental research has increasingly reported that classes conducted with digital textbooks were significantly effective in promoting students’ English ability, interest, confidence, and willingness to communicate [14]; mathematical achievement and satisfaction [15]; science achievement and self-directed learning attitude [16]; self-regulated learning and problem-solving competencies [17]; and critical thinking and problem-solving skills [18].

Heavy school bags with loads of printed textbooks are considered a serious threat to the health and wellbeing of students. Generally, digital textbooks are expected not only to address this issue, but to also help students learn more effectively. Nevertheless, there are concerns about the negative effects of digital textbooks. As students become habituated to computers or mobile devices, there may be concerns of digital overuse or addiction. For example, Villani et al. [19] found that the period of confinement in the wake of the COVID-19 pandemic had remarkable psychological consequences in students who spent their time using different mobile devices, and some of them are showing signs of becoming addicted to video games. This phenomenon raises several concerns, and attention is needed along with research related to digital textbooks.

In essence, gaining students’ trust that digital textbooks are useful and preferred tools is a prerequisite for sustainably spreading and continuing their use in education. In this regard, there are important variables to consider in research. First, it is necessary to analyze the learners’ perceived usefulness of and preference for digital textbooks to identify their attitude of the affective domain for digital textbooks. Specifically, this should be linked to learning achievement. Second, previous research on digital textbooks generally evaluated their effectiveness only within a limited period, which makes it difficult to rule out the possibility of a novelty effect, that is, the tendency for learning outcomes to initially improve when new technology is instituted, not because of any actual improvement in achievement, but in response to increased interest. Therefore, it is necessary to examine whether digital textbooks are sustainable in schools based on the results of their long-term use. In this study, we structurally examined how learning outcomes changed based on the usefulness and preference that students experience while using digital textbooks in Korean elementary school settings over three years.

3. Method

3.1. Participants

The data used in this study were obtained from a longitudinal study on the usefulness and effectiveness of digital textbooks which was suggested by the Korean Ministry of Education. In Korea, 35 digital textbook research schools were selected before the use of digital textbook in elementary schools across the country. Students from the selected schools used digital textbooks in the social studies and science classes. Third grade students (9 years old) from this research school constituted a panel and were set as the population for this longitudinal study.

3.2. Data Collection

The data were collected over three years, as the purpose of this longitudinal study was to verify sustainable achievements on the usefulness of and preference for digital textbooks. During the three-year survey period, the participants were asked to answer the survey questionnaire. They included third graders in the first year, fourth graders in the second year, and fifth graders in the third year. Since it is important to maintain and manage the survey panel above all in a longitudinal study, an online database was established to manage the survey panel from the beginning of the study. Teachers at the digital textbook research schools could access the online database in the second and third years of the study and adjusted grades and classes of the students. The researchers continued to supervise students during the three-year study period. All participants were guided through the research process and encouraged to participate voluntarily to avoid ethical issues [20].

A survey was conducted on the panelists every November during the research period. Overall, data were collected from 723 students across the 35 digital textbook research schools, and 33 students who had not answered at any point during the survey period were excluded from the analysis. Finally, 690 valid questionnaires were analyzed. The sex distribution consisted of 325 male (47.1%) and 365 female students (52.9%).

3.3. Measures

The survey questionnaire used in this study included 4 items on digital textbook usefulness, 4 on digital textbook preference, 10 on perceived achievement in the social studies class, and 10 on perceived achievement in the science class. All items were measured on a five-point Likert-type scale, from 1 (strongly disagree) to 5 (strongly agree) (see Appendix A, Appendix B, Appendix C and Appendix D).

The questionnaire was developed by the research directors before the longitudinal study was conducted. Subsequently, an expert in ICT and professors in the field of education and educational technology were involved to confirm content validity. A workshop with elementary school teachers was conducted to rectify problems in the revised questionnaire and inappropriate expressions for the developmental level of elementary school students. The alpha reliability coefficients for digital textbook usefulness, preference, perceived achievement in social studies, and science class are reported in

Table 2. Alpha reliability coefficients for the variables.

Variables	α
Digital textbook usefulness	0.87
Digital textbook preference	0.76
Perceived achievement in social studies	0.96
Perceived achievement in science class	0.95

. Since the survey respondents were elementary school students in Korea, the survey was conducted using a questionnaire written in Korean. The English translation of the questionnaire for this paper was verified through the triangulation technique by three researchers.

3.4. Data Analysis

The data were analyzed using the latent growth curve model to identify the three-year change. This model allows researchers to efficiently examine individual change on repeated measures [21] because it integrates repeated measures analysis of variance (ANOVA) and random coefficient regression models and is therefore effective in analyzing individual change. The reason is that unlike the repeated measures ANOVA, the latent growth curve model can prevent the assumption of homoscedasticity in residuals. Normally, the data structure of repeated measurement in longitudinal panel designs includes the correlation of residuals across different time points of the measurement which causes correlations between the residuals. The latent growth curve model can effectively handle correlated residuals using the framework of latent variable modeling and efficiently analyze individual change on measurement [22].

The hypothesized latent growth curve model in this study is illustrated in Figure 2. There are two types of latent variables: intercept and slope. The initial achievement variable is a latent variable that represents the initial status or intercept of the three years’ outcome variables. Therefore, the initial achievement variable indicates estimated scores of achievement for each student at baseline. Achievement growth variable is another latent variable that represents the rate of change or slope of the three years’ outcome variables. Accordingly, the achievement growth variable indicates the estimated acceleration in change of three years’ outcome variables for each student over time.

The hypothesized model is analyzed in the same way as structural equation modeling. IBM SPSS version 25 and AMOS version 25 (Armonk, NY, USA) programs were used for descriptive statistics and the latent growth curve modeling approach.

4. Results

The results of descriptive statistics for the four variables are demonstrated in

Table 3. Descriptive statistics for digital textbook usefulness and preference.

	Digital Textbook Usefulness				Digital Textbook Preference
Years	Mean	SD	Skewness	Kurtosis	Mean	SD	Skewness	Kurtosis
First year (3rd grader)	3.90	0.87	−0.66	0.40	3.93	0.71	−0.70	0.39
Second year (4th grader)	3.98	0.85	−0.70	0.41	4.04	0.74	−0.74	0.20
Third year (5th grader)	3.90	0.89	−0.72	0.63	4.05	0.73	−0.85	0.70

and

Table 4. Descriptive statistics for perceived achievement in social studies and science class.

	Perceived Achievement in Social Studies Class				Perceived Achievement in Science Class
Years	Mean	SD	Skewness	Kurtosis	Mean	SD	Skewness	Kurtosis
First year (3rd grader)	3.62	0.89	−0.13	−0.17	3.75	0.73	−0.28	−0.15
Second year (4th grader)	3.73	0.83	−0.11	−0.20	3.86	0.69	−0.23	−0.57
Third year (5th grader)	3.79	0.80	−0.07	−0.59	3.87	0.60	−0.15	−0.56

. Digital textbook usefulness indicated that the mean value in the second year increased marginally, but in the third year, it fell to the same level as in the first year. Meanwhile, digital textbook preference showed a marginal increase in the second year and remained at the same level in the third year. It was found that the three-year trend of academic achievement increased marginally in both social studies and science classes.

In order to decide the type of estimators, the nature of the data was verified to discern whether the multivariate normality assumption had been met, based on skewness and kurtosis [23]. As seen in the table, skewness and kurtosis ranged from −0.85 to −0.07 and −0.59 to 0.70. Compared to the results of data normality and cutoff point (skewness and kurtosis as “±2 and ±7”), the value of skewness and kurtosis are in the adequate range. Since the type of variable is categorical and the number of categories is at least five, the use of maximum likelihood estimation is appropriate for further analysis [24].

Table 5. Parameter estimates for digital textbook usefulness, preference, and achievement in social studies.

			β	SE	CR	p
Initial usefulness	→	Initial achievement	0.47	0.10	4.88	<0.01
Initial usefulness	→	Achievement growth	−0.14	0.09	−1.56	0.12
Usefulness growth	→	Achievement growth	0.16	0.13	1.26	0.21
Initial preference	→	Initial achievement	0.45	0.10	4.44	<0.01
Initial preference	→	Achievement growth	0.04	0.10	0.44	0.66
Preference growth	→	Achievement growth	0.42	0.13	3.34	<0.01

shows the parameter estimates of all paths among usefulness, preference, and achievement in social studies. The path coefficient from initial usefulness to initial achievement (β = 0.47, p < 0.01), initial preference to initial achievement (β = 0.45, p < 0.01), and preference growth to achievement growth (β = 0.42, p < 0.01) was significant. However, the path coefficient from initial usefulness to achievement growth, usefulness growth to achievement growth, and initial preference to achievement growth was not significant.

Table 6. Parameter estimates for digital textbook usefulness, preference, and achievement in science class.

			β	SE	CR	p
Initial usefulness	→	Initial achievement	0.44	0.09	4.79	<0.01
Initial usefulness	→	Achievement growth	−0.13	0.09	−1.51	0.13
Usefulness growth	→	Achievement growth	0.19	0.12	1.63	0.10
Initial preference	→	Initial achievement	0.41	0.10	4.24	<0.01
Initial preference	→	Achievement growth	0.05	0.09	0.53	0.59
Preference growth	→	Achievement growth	0.42	0.12	3.57	<0.01

shows the parameter estimates of all paths among usefulness, preference and achievement in science class. The results of the significance path are the same as the model with social studies above.

In summary, the usefulness of and preference for digital textbooks perceived by students had a significant effect on academic achievement. When the use of digital textbooks continues, it can be seen that significant results appear depending on the increase in their preference. Figure 3 and Figure 4 illustrate the structural parameter estimates for the latent growth curve model of social studies and science classes with significant paths.

5. Discussion

Overall, 690 valid elementary school students participated in the study. They used digital textbooks with various online learning content and information for three consecutive years. Using the latent growth curve model, the effects of usefulness and preference for digital textbooks on academic achievement were examined. The results showed that digital textbooks had a sustainable significant effect on learning.

Figure 3 and Figure 4 demonstrate that there are numerical differences between the social studies and science subjects, but we found similar results in the significance of the parameter estimate. Specifically, the achievement level according to the usefulness of and preference for digital textbooks was significant in both subjects. Therefore, regardless of the characteristics of each subject, it can be inferred that the overall perception of digital textbooks by students is positive. These results indicate that digital textbooks can be naturally accepted by learners in the school environment as an alternative learning tool.

Considering the research results in detail, which showed that the higher the initial usefulness and initial preference, the greater the initial perceived achievement, we highlight the following implications. First, in terms of usefulness, it is necessary to develop the unique characteristics of digital textbooks for learners to use them as powerful learning tools. Regarding preference, the user interface and user experience that students prefer and require should be continuously updated so that students can consistently consider digital textbooks as attractive tools and enhance convenience.

Interestingly, the usefulness of digital textbooks increased in the second year and decreased marginally in the third year, while the preference for them steadily improved in all the three years. Previous studies have reported consistently improved satisfaction or usefulness of digital textbooks [25,26,27]. The unexpected result showing that the usefulness of digital textbooks decreased in the third year can be interpreted as follows. First, it might be assumed that the positive judgment on usefulness relatively slowed down as students became accustomed to digital textbooks over time, compared to the early days when they actively used them. Another possible conjecture may be that the usefulness of digital textbooks experienced by learners has significantly declined. Effectively, as it was a long-term study spanning over three years, there were expectations for the application of rapidly developing technology, and the disappointment of learners who were not satisfied with it may have been reflected in the research results. Therefore, it is imperative to conduct in-depth research, such as observation and interviews, for contextual understanding in the classrooms.

Meanwhile, it can be inferred that preferences increased over the years as students discovered the advantages of digital textbooks and believed that they were helpful in class. The research results showing a continuous positive correlation between preference and academic achievement will be an important indicator that can be predicted to have a positive effect on excellence in schools as digital textbooks are steadily used in the future. These results may reflect the characteristics of students who are “digital natives” with a high level of digital literacy [28], and it can be understood that the preference for various features on digital textbooks was high, which led to positive learning outcomes. This would signal that new technology environments, such as digital textbooks, will ease concerns about technical barriers or resistance when applied to learners. In summary, the usefulness of and preference for digital textbooks perceived by students had a significant effect on academic achievement, and when their use continues, it may be seen that significant results appear, depending on how much their preference increases. Figure 3 illustrates the structural parameter estimates for the latent growth curve model of social studies and science classes with significant paths.

6. Conclusions

This study was conducted to explore the possibility of sustainable education using digital textbooks over a long period with large-scale samples. Despite the significant results and implications, this study has the following limitations. First, its research constructs were related to only two exogenous variables, and an indirect perceived endogenous variable. These were inevitable considering the research environment and research design, but it would be prudent to select more or direct variables for sophisticated results. In addition, although digital textbooks are applied from elementary school to high school in Korea, this study involved only elementary school students; therefore, caution should be exercised in generalizing the results.

Despite these limitations, the study remains significant. First, sustainable educational effects were verified through a long-term three-year study covering the same participants. Second, relationships among significant variables in learning—usefulness, preference, and achievement—were examined through structural equation modeling. Third, through research on the application of digital textbooks in the school field, the possibility of radical changes in education in a high-tech society was explored.

Accordingly, this study has the following implications. First, the results of the research were not temporary, nor did it concern the so-called novelty effects from short-term experiments; they were derived through continuous research over three years. Therefore, it can be regarded as a consistent achievement with high reliability. Specifically, it was suggested that digital textbooks can provide sustainable help to students. Second, the methodology applied in this study explored the detailed relationship among instructional variables. Specifically, a structural relationship was identified on the effect of students’ usefulness or preference for digital textbooks on academic achievement. Therefore, to improve the effectiveness of using digital textbooks in schools, this study could be one of the criteria for research on strategies to present useful and attractive learning materials and contents in digital textbooks. Third, this study can be used as a reference case when similar technologies or devices are applied to schools according to the development of science and technology in the future.

Meanwhile, with remote learning gaining popularity in the wake of the COVID-19 pandemic, the demand for sustainable digital-based learning and digital textbook environments is expanding. To prepare for this era, the development of digital textbooks for the next generation has been suggested, and the following points should be addressed [4]. First, this development must be a flexible configuration. Microlearning content considering the student level should be supported, and the content should be easily reconstructed, extracted, and connected to external materials after authoring. Second, this development must be a convergent connection. It is necessary to connect the core concepts in one subject with those in other subjects, grades, and school levels, and high-contextual cases should be presented. These core concepts should be developed and utilized by learning modules that can be used for each academic achievement standard. Third, various instructional activities should be supported. Teaching–learning models, such as individualized learning, cooperative learning, and problem-solving learning, should be supported for teachers to use in different learning environments. Fourth, it is necessary to establish a cloud-based shared learning environment. Instead of storing an individual’s learning history on an individual computer or tablet PC, an environment [29] is needed to access and utilize it and work with fellow students simultaneously anytime, anywhere. Fifth, a data-based system structure is required. Data accumulated in the learning process should be collected, analyzed, diagnosed, and prescribed using artificial intelligence technology to improve learning effectiveness.

In addition, as mentioned earlier, attention should be paid to the negative effects of digital textbooks. Most of the studies have demonstrated the positive effects of digital textbooks on learning, but it is also worth considering issues such as digital addiction [30,31,32].

Through this study, which examined the application of a sustainable digital environment to schools through multi-year research on digital textbooks, future studies can explore the comprehensive effects of digital textbooks—or even other technologies—such as diverse cognitive domains or school operations. Furthermore, it is necessary to consider the overall impact of the digital environment as well as digital textbooks on school education from various angles, including positive and negative aspects, and to systematically design and apply these results to sustainable future education.