The Impact of Educational Games on Learning Outcomes: Evidence From a Meta-Analysis

The objective of this study is to examine and compare the impact of serious games and gamification on learning achievement and motivation. The results of the meta-analysis indicate that gamification has a more positive influence on learning achievement and motivation compared to serious games. The analysis reveals that gamification demonstrates a stronger impact on extrinsic motivation than on intrinsic motivation. Serious games have a more positive effect on intrinsic motivation in comparison to extrinsic motivation. The overall outcome suggests that gamification has relatively stronger effects than serious games. While the impact on extrinsic motivation is more significant with both approaches, serious games excel in fostering intrinsic motivation. However, further research is recommended to investigate the specific mechanisms that drive these effects and to identify optimal strategies for implementing serious games and gamification in diverse educational settings.


INTROdUCTION
Numerous studies have been committed to serious games and gamification (e.g.Raju et al., 2021;Krath & von Korflesch (2021); Tan et al., 2021;Högberg et al., 2019).According to Katrin Becker's study (2015), a serious game can be defined as a digital game that is designed for a purpose beyond entertainment.It is intended to educate or train individuals while also providing an engaging and interactive gaming experience.Serious games are often used as a tool for learning, communication, or decision-making in various fields such as education, healthcare, business, and defense.On the other hand, gamification refers to the use of game design elements and principles in non-game contexts, with the aim of increasing engagement, motivation, and participation.It involves incorporating game-like features such as rewards, challenges, levels, and leaderboards into activities that are not inherently game-like.Gamification can be seen as a means to enhance user experience and drive behavioral change by applying game mechanics and psychology to real-world situations.To sum up, while serious games are designed as digital games with a specific educational or training purpose, gamification involves applying game elements to non-game contexts to enhance user engagement and motivation.
According to Kim and Lee (2015), a game is characterized by an engaging series of choices that allow players to achieve specific and compelling goals.As technological advancements have facilitated the integration of games or game elements in educational settings, educators have embraced various game-related approaches to enhance student interest, enjoyment, and instructional effectiveness (Kim, Song, Lockee, & Burton, 2018).The growing popularity of game-related approaches has prompted researchers to investigate their hypothesized motivational impact in instructional contexts (Kim et al., 2018;Sailer & Homner, 2020).Games could be considered a beneficial tool to enhance learning experiences and teaching strategies (Gee, 2013).
Different approaches to game implementation result in distinct game-related practices.Two common approaches include serious games and gamification (Loh, Sheng, Ifenthaler, 2015;Becker, 2015).Serious games are digital games designed not solely for entertainment purposes, but to be used for educational, training, or healthcare purposes (Loh et al., 2015).On the other hand, gamification refers to the use of game mechanics in non-gaming contexts to engage learners, enhance learning, and solve problems (Kapp, 2012;Kim et al., 2018;Yu, 2015).
Gamification activities and processes can be employed by educators to create game-related learning environments and address learning challenges (Kim et al., 2018;van Grove, 2011;Werbach & Hunter, 2012).However, unlike serious games, the primary emphasis of gamification is on incorporating game elements into pedagogical practices (Kim et al., 2018).It is important to note that gamification is not a distinct form of digital game in itself (Loh et al., 2015).Therefore, educators should consider utilizing gamification alongside digital games (Domínguez et al., 2013).
Hence, it is essential to differentiate between the serious game and gamification approaches, as they have distinct definitions and potential impacts on pedagogical practices.By recognizing their unique characteristics, we can effectively evaluate and compare the efficiency of these gamerelated approaches.
To measure the efficiency of game implementation, various dimensions can be considered.A commonly used criterion is learning achievement, which evaluates the extent to which learners have progressed in their academic performance (Kim et al., 2018).Additionally, the motivational power of games plays a significant role in assessing the efficacy of game-related approaches (Sailer & Homner, 2020).Motivation can be further classified into intrinsic and extrinsic motivations (Ryan & Deci, 2000a;2000b).Therefore, we can adopt learning achievement and motivation as criteria for evaluating and comparing the efficiency of these game-related approaches in pedagogical practices.
Given the significance of this study, its primary objective is to validate the effectiveness of game implementation in pedagogical practices through meta-analyses.By utilizing statistical findings, we can provide compelling evidence to support game implementation as an innovative approach, rather than a trivial one, in pedagogical practices (Kim et al., 2018;Sailer & Homner, 2020).
Moreover, this study aims to differentiate between serious games and gamification, both theoretically and in terms of their practical effects on learning achievement and motivation.It is essential to avoid confusion between these game-related concepts.By comparing the effects of these approaches, we can investigate the specific contexts in which each approach is most effective.Consequently, educators can maximize the efficiency of game-related approaches in pedagogical practices.
Given the significance of this study, our primary objective is to validate the effectiveness of game implementation in pedagogical practices through meta-analyses.By analyzing statistical findings, we can provide persuasive evidence to support the use of games as an innovative approach in pedagogical practices (Kim et al., 2018;Sailer & Homner, 2020), demonstrating that it is not a trivial approach.
Additionally, we aim to differentiate between serious games and gamification in terms of their theoretical analyses and practical effects on learning achievement and motivation.It is important to clearly distinguish between these two game-related concepts.By comparing the effects of these approaches, we can investigate the specific contexts in which each approach can be highly efficient.This will allow educators to maximize the effectiveness of game-related approaches in pedagogical practices.
Moreover, based on the distinctions between serious games and gamification, future research can focus on refining pedagogical models related to game implementation.Since serious games and gamification represent different applications of games, meta-analyses can highlight the essential qualities of each approach for researchers to consider when designing and refining models.
In line with our research objectives, we have investigated and compared the effects of serious games and gamification on learning achievement and motivation.This has led us to formulate the following two research questions: RQ1: Do the approaches of serious games and gamification have different impacts on learning achievement?RQ2: Do the approaches of serious games and gamification have different impacts on motivation?
Given that motivation encompasses both intrinsic and extrinsic motivation, it is important to examine the overall impact of game-related approaches on these motivation subtypes.Furthermore, it is crucial to compare the effects of different game-related approaches on both intrinsic and extrinsic motivation.As a result, we have formulated a third research question related to motivation subtypes: RQ3: Do game-related approaches have distinct effects on intrinsic motivation and extrinsic motivation?
To ensure a solid foundation for conducting meta-analyses, it is essential to examine previous studies that provide academic support.

LITERATURE REVIEw
In this section, we will explore and analyze the existing research to distinguish between serious games and gamification.We will focus on theoretical concepts and practical contexts as established by past studies.

differentiating Gamification From Serious Games: A Focus on Gamefulness
The study found significant and positive relationships between flow experience and intrinsic motivation, specifically intrinsic motivation to know and intrinsic motivation to experience simulation, as well as the three types of extrinsic motivation.However, there was a negative correlation between flow experience and intrinsic motivation towards accomplishments and amotivation.Additionally, there was a significant difference between the mean scores of pre-tests and post-tests, indicating the effectiveness of the serious game in promoting medical students' motivation, flow, and learning achievements (Zairi et al., 2022).
Recent advancements in serious games and gamification have revealed significant findings.Integrating schema into games enhances knowledge acquisition, retention, cognitive load, and motivation (Ye et al., 2022).Game-based features in intelligent learning environments boost engagement, motivation, attention, enjoyment, and learning achievements (Sun et al., 2023).Lowering game difficulty increases positive emotions, learning motivation, and has consistent effects across different goal orientations, with no significant impact on performance (Cao et al., 2022).Gamified learning improves students' motivation, even amid challenges like the pandemic (Chen et al., 2023).Non-digital gamification enhances course satisfaction, while mixed gamification enhances cognitive engagement (Qiao et al., 2023).Additionally, integrating Escape Rooms into mathematics teaching improves achievement, motivation, autonomy, and addresses negative attitudes towards the subject (Saleh Alabdulaziz, 2023).
A crucial factor in distinguishing these terms is the differentiation between playing and gaming in terms of the types of activities involved (Caillois, 1961)."Playing" refers to spontaneous, unrestricted, and expressive actions without following set rules.On the other hand, "gaming" refers to activities that are rule-based and goal-oriented (Caillois, 1961).According to Caillois (1961), games should involve voluntary and enjoyable activities with explicit rule systems and measurable outcomes, creating goods of external value (Salen & Zimmermann, 2004).Consistent with the distinction between playing and gaming, McGonigal (2011) has introduced playfulness and gamefulness.Accordingly, McGonigal (2011) has proposed four fundamental features of games: goals, rules, feedback system, and free will.Goals can provide platers with the purposes for playing; Rules present the limitations and boundaries of achieving the goals; feedback systems enable players to reach the goals when they respect the game rules; learners' free will can guarantee active participation in the activities and concentration on the rules (McGonigal, 2011).Even if games involve other features, such as storytelling, interactivity, or rewarding systems, these features develop and enrich the fundamental features (Matallaoui et al., 2017).
Additionally, Deterding et al. (2011) have defined gamification as the use of game design elements in non-game contexts and accordingly proposed two dimensions, whole versus parts and gaming versus playing, to differentiate gamification from other related concepts.Whole versus parts demonstrates the extent to which a product is using gaming elements (Deterding et al., 2011;Matallaoui et al., 2017).In contrast, gaming versus playing reflects whether the product involves rule-bounded and outcome-related elements or just consists of the playing aspect (Deterding et al., 2011;Matallaoui et al., 2017).
Gamification partly requires gaming elements with other aspects of the product untouched, whereas serious games require complete game designs with an education or learning background (Deterding et al., 2011;Matallaoui et al., 2017).Gamification also requires rule-based goal-oriented designs that encourage players to progress by completing tasks or surpassing others (Deterding et al., 2011;Matallaoui et al., 2017).
However, although the researchers have discussed the distinction between playing and gaming, experimental procedures conducted by Salen & Zimmermann (2004), Barr Barr, Nobel, and Biddle (2007), and Groh (2011) have demonstrated that people can integrate these concepts and that the distinction might remain theoretical to some extent.
Gamification involves integrating gaming elements into a product while keeping other aspects unchanged, whereas serious games require complete game designs with an educational or learning background (Deterding et al., 2011;Matallaoui et al., 2017).Gamification relies on rule-based, goaloriented designs that motivate players to progress by completing tasks or surpassing others (Deterding et al., 2011;Matallaoui et al., 2017).
However, research conducted by Salen & Zimmermann (2004), Barr Barr, Nobel, and Biddle (2007), and Groh (2011) has shown that individuals can integrate the concepts of playing and gaming, suggesting that the distinction between the two may be more theoretical than practical.Oliveira and Petersen (2014) argue that serious games emphasize the use of Information and Communications Technology (ICT) to create engaging experiences that promote awareness, understanding, and mastery of specific concepts or skills.In contrast, gamification focuses on leveraging ICT to facilitate or constrain specific behaviors based on immersive experiences (Oliveira & Petersen, 2014).While both serious games and gamification can engage players, serious games typically provide implicit engagement in a more comprehensive manner, while gamification offers engagement in specific behaviors within a more integrated framework (Oliveira & Petersen, 2014), which aligns with the findings of Deterding et al. (2011).
In terms of practices, serious games typically require comprehensive game designs that span throughout the activities, while gamification can be implemented without the need for actual games, by incorporating elements into everyday contexts to motivate and engage players (Oliveira & Petersen, 2014).Serious games involve the use of specific rules and actions in a cohesive manner, encouraging players to compete with others.They can also be played in teams to promote collaborative awareness and foster community spirit.On the other hand, gamification draws from game designs but does not necessarily require the form of traditional games.It allows players to immerse themselves in gamified designs and enhance their performance through self-challenges (Oliveira & Petersen, 2014).Additionally, serious games often involve winners and losers after competitions, while gamification emphasizes slightly competitive game elements that encourage players to make progress regardless of others' performance (Oliveira & Petersen, 2014).Although it has been shown by Salen & Zimmermann (2004), Barr et al. (2007), and Groh (2011) that these concepts can be integrated and that the distinction may be somewhat theoretical, the differences between gamification and serious games still warrant discussion, as these approaches to utilizing games require slightly different orientations and features in pedagogical practices.

Comparing Gamification and Serious Games in Gamified Contexts
In their study, Aldemir, Ataş, and Celik (2019) have introduced the Gamified Environment and Learning Design (GELD) model, which outlines the elements and flexibility of gamified contexts in game-related approaches.The model consists of five key components: gamified environment, gamified course, design, game elements, and people.It is important to note that these elements may overlap, indicating the dynamic relationship between the gamified learning experience and the broader context (Aldemir, Ataş, & Celik, 2019).
The gamified environment holds a dominant and inclusive role in the GELD model as it sets the overall direction for the practices.A successful gamified environment relies on finding a balance between fun and seriousness and implementing motivating strategies (Aldemir et al., 2019).
When creating efficient gamified environments, instructors must strike a balance between fun and seriousness, ensuring consistency between playful elements and the educational purpose (Kapp, 2012).The primary objective of gamifying educational environments is to make serious activities enjoyable (Deterding et al., 2011;Zichermann & Cunningham, 2011;Werbach & Hunter, 2012).It is worth noting that the level of seriousness incorporated in gamified procedures determines the type of game-related pedagogical practices.Serious games emphasize the integration of seriousness within playful experiences, while gamification tends to have a lower level of seriousness.
Therefore, serious games place greater emphasis on incorporating seriousness for educational purposes within gamified environments, while gamification focuses more on entertainment.Instructors should distinguish between these game-related approaches and adapt gamified procedures according to their pedagogical goals.
When considering conducive conditions for motivation, psychologically safe environments play a crucial role.These environments allow participants to freely express their opinions and make progress without fear of failure (Aldemir et al., 2019;Kapp, 2012).During gamification procedures, participants experience a sense of satisfaction and positive motivation once they achieve their goals of knowledge or skill mastery (Deterding et al., 2011).Instructors should also provide progressive step-by-step procedures, ensuring mastery and facilitating participants' adaptation to gamified experiences.This approach contributes to long-lasting motivation (Aldemir et al., 2019;Zichermann & Cunningham, 2011).
Hence, the need for motivating designs underscores the importance of motivation in implementing game-related approaches.In addition to assessing the effectiveness of pedagogies through learning outcomes, instructors should also focus on fostering learners' motivation in gamified experiences (Kim et al., 2018).Moreover, considering the differences between serious games and gamification, it is pertinent to discuss the potential impact of these approaches on intrinsic and extrinsic motivation.This aligns with the objectives of our study.

METHOdOLOGy
This section details the research methods used to conduct the meta-analyses.The methods include identification, screening, eligibility, and inclusion criteria.Additionally, we examined the meta-analysis parameters based on the experimental scales employed in the included studies.

Literature Search for Identification
To ensure research sensitivity and scope, we adopted the research criteria used in the studies by Seaborn and Fel (2015) and Sailer and Homner (2020) for our literature search.We did not impose restrictions on the publication year.The search scope encompassed databases such as ERIC, IEEE Xplore, PubMed, SpringerLink, and Web of Science.
We utilized the following keywords in our search: gamification or serious game*, learning, and experiment*.Initially, our search yielded 7109 results.We further refined the results by using the keywords learning achievement and motivation.Upon removing duplicate records and refining the initial results, we identified 172 potentially eligible records.

Screening and Eligibility Criteria
In order to select eligible studies, we applied the following inclusion criteria: 1) Publication Language: Studies had to be published in English.
2) Research Topic: Studies needed to clearly describe the effectiveness of gamification or serious games on learning achievement or motivation, or present comparisons between these game-related approaches.3) Research Design: Studies were required to use quantitative statistical methods to examine the effects of game-related approaches on learning achievement or motivation.4) Experimental Conditions: Studies had to include a comparison between an experimental group and a control group, with at least one game-related condition compared to at least one condition based on another instructional approach.5) Availability of Statistical Data: Studies needed to report sufficient statistical findings, such as participant numbers, means, and standard deviations, to enable the application of meta-analytic techniques.
During the selection process, we reviewed the abstracts for screening and the full-text contents for eligibility.Any studies that did not meet the following exclusion criteria were included: 1) Not published in English.2) Did not involve experimental or statistical procedures, but were instead reviews.
3) Did not clearly describe the experimental topics or the target items assessed in the experimental procedures.4) Did not present sufficient information to allow for the application of meta-analytical techniques.

Selection of Final Sample
We screened the initial literature records and identified a total of 57 studies that met the inclusion criteria (see Table 1).These studies focused on examining the effects on motivation.In Table 1, we have provided a summary of the specific motivation-related concepts that were investigated in each study.If a study described motivation in a general sense, we categorized it as "uncategorized motivation."However, if a study described specific motivation-related concepts, we classified them into corresponding motivation subtypes according to the criteria outlined in section 4.3.1.

Statistical Analysis
To perform meta-analyses, we integrated multiple sets of data due to the similarity of research dimensions in various studies.We utilized the "Combine Means and SDs Into One Group" program developed by The Chinese University of Hong Kong, which can be found at https://www.obg.cuhk.edu.hk/ResearchSupport/StatTools/CombineMeansSDs_Pgm.php, to combine the collected data.
For conducting the meta-analyses, we employed STATA 15.As the heterogeneity among experimental conditions and participant samples influences the analysis models (Borenstein, Hedges, Higgins, & Rothstein, 2009), we carefully considered the range of heterogeneity within the data.
To address the diverse scales used in the studies' data reporting, we applied Cohen's d, a standardized mean difference (SMD) statistical parameter, to assess the difference between means of the experimental and control groups based on the pooled standard deviation (Borenstein et al., 2009).

do Serious Game and Gamification Approaches Impact Learning Achievement differently?
Table 1 provides an overview of relevant studies on the effects of game-related approaches on learning achievement.Using the STATA 15 platform, we conducted data analysis and obtained the following results.

Examining Overall Effects on Learning Achievement
Table 2 shows the heterogeneity test results of the dataset, indicating significant heterogeneity (I 2 = 81.0%,Cochran's Q = 242.13,p < 0.05).Therefore, we used a random-effects model to investigate the effects of game-related pedagogical models on learning achievement.
The overall effects on learning achievement, and the random-effects model revealed a significant positive impact (d = 0.480, z = 7.730, p < 0.05, 95% CI [0.358, 0.601]) of game-related approaches on learning achievement.
Both subgroups had high heterogeneity within them (p < 0.05), but low heterogeneity between them (p = 0.051 > 0.05).The heterogeneity in the gamification subgroup (I 2 = 86.0%,p < 0.05) was significantly higher than in the serious game subgroup (I 2 = 74.6%,p < 0.05).Overall, gamification has a more positive and varying impact on learning achievement compared to serious games.

Factors Influencing Heterogeneity and Publication Bias
We conducted a meta-analysis regression to analyze variables that may contribute to the heterogeneity.Variables included year, pedagogy (serious game or gamification), sample size, mean and standard deviation of the experimental and control groups.
Results showed that mean values of the experimental and control groups were significant factors (p < 0.05) contributing to heterogeneity.Different studies use different scales for target items, leading to variations in mean values and the use of standardized mean difference.
Through sensitivity analysis, we found that the study by Hussein et al. (2019) had the most influence in the serious game approach, while the study by Duggal et al. (2021) had the most influence in the gamification approach.
Publication bias was assessed using Egger's test, which showed no significant publication bias (p = 0.138 > 0.1).The funnel plot did not display significant asymmetries, except for one insignificant data point.The trim and fill analysis confirmed that the effects on motivation remained statistically significant.
In the subgroup analysis comparing the effects of the serious game approach with those of the gamification approach on motivation, both subgroups showed statistically significant results.The serious game subgroup had a significant effect on motivation (d = 0.323, z = 2.594, p = 0.009 < 0.05, 95% CI [0.079, 0.566]), while the gamification subgroup had a more significant effect (d = 0.660, z = 6.521, p < 0.05, 95% CI [0.462, 0.858]).The heterogeneity was high in both subgroups, with the serious game subgroup showing significantly higher heterogeneity (I 2 = 90.4%,p < 0.05) compared to the gamification subgroup (I 2 = 87.8%,p < 0.05).Overall, the gamification approach had a more significant and stable impact on motivation compared to the serious game approach.
In order to investigate the potential sources of heterogeneity, we conducted a meta-analysis regression to analyze the variables influencing heterogeneity, using the same variable names as in section 4.1.3.
The regression results (Table 3) revealed that the approach (p = 0.007 < 0.05), Em (p < 0.05), and Cm (p < 0.05) were the main factors contributing to significant heterogeneity.This suggests that the effects of the serious game and gamification approaches on motivation vary significantly.Additionally, different studies used different scales for participants' target item, resulting in varying means or standard deviations.This justifies the use of Standardized Mean Difference (SMD).
We also conducted a sensitivity analysis to identify influential studies.The results showed that the study by O'Garra et al. (2021) significantly decreased the overall effects of serious games on motivation, while the studies by Chang et al. (2018) and Pimentel et al. (2021) significantly increased the overall effects.This indicates relatively unstable effects of serious games on motivation.On the other hand, the study by Haruna et al. (2018) had the most influential effect, increasing the overall effects of the gamification approach on motivation.
Regarding publication bias, the Egger's test results (Table 4) indicated that there is no obvious publication bias (p = 0.233 > 0.1).The funnel plot showed no apparent asymmetries, except for a few dots representing highly significant effects.The trim and fill analysis did not alter the set of data, confirming that the effects on motivation have statistical significance.

do Game-Related Approaches Have differential Effects on Intrinsic and Extrinsic Motivation?
This research question aims to compare the effects of game-related approaches on intrinsic and extrinsic motivation.To address this, we need to classify the motivation-related concepts in the extracted studies as either intrinsic or extrinsic motivation.The following criteria were used for classification.
According to the Self-Determination Theory (SDT) (Ryan & Deci, 2000a;2000b), intrinsic motivation is characterized by inherent satisfaction and spontaneous behaviors, while extrinsic motivation emphasizes instrumental value and the potential outcomes of events.Additionally, intrinsic motivation is associated with competence and autonomy at an inherent level, whereas extrinsic motivation involves competence, autonomy, and relatedness, often through the presence of rewards within a supportive community (Kim et al., 2018;Ryan & Deci, 2000a;2000b).Intrinsic motivation is driven by a sense of spontaneous satisfaction, while extrinsic motivation focuses on external outcomes.Based on these distinctions, we have classified the motivation-related concepts found in the extracted studies (refer to Table 1).

Analysis of the Overall Effects of Game-Related Approaches on Intrinsic and Extrinsic Motivation
The dataset analysis revealed significant heterogeneity (I 2 = 89.0%,Cochran's Q = 336.08,p < 0.05, see Table 2) among the studies.Therefore, we conducted a random-effects model to examine the effects of game-related pedagogical models on motivation.
Regarding subgroup heterogeneity, all subgroups exhibited high heterogeneity (p < 0.05), but the heterogeneity between groups was relatively low (p = 0.367 > 0.05).Notably, the heterogeneity in the extrinsic motivation subgroup (I 2 = 91.1%,p < 0.05) and intrinsic motivation subgroup (I 2 = 88.8%,p < 0.05) was higher than that in the uncategorized motivation subgroup (I 2 = 85.1%, p < 0.05).This suggests that game-related approaches have slightly varying impacts on extrinsic motivation compared to intrinsic motivation.

Analysis of the Differences in Effects of Game-Related Approaches on Intrinsic and Extrinsic Motivation
In addition to the overall effects analysis, we conducted subgroup analyses to examine the specific game-related approaches and their effects on intrinsic and extrinsic motivation.This allowed us to assess the differences in impacts between the two motivation types within each approach.
For the serious game approach, the results showed a significant effect on extrinsic motivation (d = 0.352, z = 2.118, p = 0.034 < 0.05, 95% CI [0.026, 0.677]), while the effect on intrinsic motivation was not significant (d = 0.205, z = 0.823, p = 0.411 > 0.05, 95% CI [-0.284, 0.695]).These findings indicate that the serious game approach has a greater positive impact on intrinsic motivation compared to extrinsic motivation, and that the effects on extrinsic motivation are notably unstable.
For the gamification approach, the results demonstrated a significant effect on intrinsic motivation (d = 0.481, z = 3.404, p < 0.05, 95% CI [0.204, 0.758]), as well as a significant effect on extrinsic motivation (d = 0.603, z = 4.374, p < 0.05, 95% CI [0.333,0.873]).These findings suggest that the gamification approach has a greater positive impact on extrinsic motivation compared to intrinsic motivation, and that the positive effects on both motivation types are consistently stable.

Analysis of Heterogeneity Factors and Examination of Publication Bias
To investigate potential sources of heterogeneity, we conducted a meta-analysis regression to analyze the variables that could influence the heterogeneity.We used the same variable names as in 4.1.3and included the variable "motivation" (with motivation subtypes coded as follows: 1 = uncategorized motivation, 2 = intrinsic motivation, 3 = extrinsic motivation).
The regression results (see Table 3) revealed that approach (p = 0.012 < 0.05), Em (p < 0.05), and Cm (p < 0.05) are the main factors contributing to significant heterogeneity.This indicates that the motivation subtypes themselves are not the sources of heterogeneity, suggesting that the extracted studies on motivation are stable.
To identify influential studies, we conducted a sensitivity analysis.The results showed that the studies by Alcalá & Garijo (2017), Haruna et al. (2018), andO'Garra et al. (2021) were the most influential among the extracted studies.
Regarding publication bias, the Egger's test results (see Table 4) indicated that there was no significant publication bias (p = 0.353 > 0.1).The funnel plot did not show any apparent asymmetries.Additionally, the trim and fill analysis did not alter the results, confirming the statistical significance of the effects on motivation.

Variations in demographics and Test Methods
Before conducting a comparison of this study, it is important to consider the variations in demographics and test methods.These variations can affect the generalizability and reliability of the findings.Different studies may have diverse participant demographics, including age, gender, educational background, and cultural factors.These variations can influence how individuals engage with serious games or gamification and their response to these interventions.The methodologies employed in studies can vary, including the types of assessments used, the duration of the intervention, and the specific learning outcomes measured.Some studies may use pre-and post-tests to evaluate learning achievement, while others may focus on self-report measures of motivation.The choice of test methods can impact the validity and reliability of the results.
Considering these variations in demographics and test methods is crucial while conducting a meta-analysis to ensure that the findings are robust and applicable to a broader population.It is also important for researchers to carefully evaluate the methodology and limitations of individual studies before drawing conclusions from the meta-analysis.

dISCUSSION
This section will discuss the implications of the research findings.The meta-analyses results indicate that the effects of gamification on learning achievement and motivation are more significant compared to serious games.Therefore, we will explore the factors that may contribute to these differences in effects on learning achievement and motivation.

Factors Contributing to different Effects of Serious Games and Gamification on Learning Achievement and Motivation
Serious games are designed specifically for educational purposes, incorporating complete game designs (Deterding et al., 2011;Matallaoui et al., 2017).By utilizing serious games, game-based learning can enhance information processing ability (Hayes, 2008), problem-solving capability (Mayer & Wittrock, 2006), learning effectiveness (Lin et al., 2021;Papastergious, 2009), and independent learning capability (Yien, Hung, Hwang, & Lin, 2011).These characteristics make serious games an effective approach for motivating learners to make academic progress.
On the other hand, gamification involves incorporating game elements into the overall design (Deterding et al., 2011;Matallaoui et al., 2017).Like game-based learning with serious games, gamification utilizes game mechanics to provide motivating activities that enhance motivation, learning, and problem-solving skills (Kim et al., 2018).However, gamification is not developed with specific educational purposes in mind; rather, it focuses on creating a set of incentive activities and systematic processes based on game characteristics (Kim et al., 2018).
Games can stimulate learners' interest in tasks through playful experiences, and gamification takes advantage of this by creating more immersive activities than traditional game-based learning (Kim et al., 2018).This increased immersion is associated with learning achievement and motivation (Kim et al., 2018;Li et al., 2012;Su & Cheng, 2015).Consequently, gamification is capable of fostering a high level of engagement among learners.
It is important to note that immersive experiences in gamification heavily rely on learner engagement.However, there are various uncontrollable external and internal factors that can influence the degree to which learners make progress in their learning (Kim et al., 2018;Radoff, 2011).These factors include the design of the gamification system, the pedagogical context, as well as learners' frustration and distraction.As a result, gamification may have less consistent effects on learning achievements compared to serious games, as the immersive experiences in gamification are easily influenced by external distractions or internal reluctance (Kim et al., 2018;Radoff, 2011).
In summary, games that do not have specific educational purposes can offer unlimited playful experiences that can significantly impact learning achievements and motivation.Therefore, gamification may have a stronger influence on learning achievement and motivation compared to serious games.However, it is important to recognize that the effects of gamification may be unstable due to its dependence on learner engagement, which can be influenced by external and internal factors.

Factors Contributing to different Effects of Game-Related Approaches on Intrinsic and Extrinsic Motivation
The findings indicate that game-related approaches generally have a more positive impact on extrinsic motivation, with gamification specifically showing stronger effects on extrinsic motivation compared to intrinsic motivation.This may be due to the controllable nature of extrinsic conditions.Extrinsic motivation is influenced by external factors such as rewards, pressure, or punishment, while intrinsic motivation arises from internal reactions such as pleasure, curiosity, or interest (Kim et al., 2018;Ryan & Deci, 2000a;2000b).
It is worth noting that not all individuals can easily achieve intrinsic motivation in specific learning contexts due to its abstract nature and inherent effects, whereas most individuals can find motivation from external factors that can be controlled (Kim et al., 2018).As a result, educators often focus on these external factors to stimulate learners' interest and employ strategies to enhance their extrinsic motivation (Kim et al., 2018).
Furthermore, the results demonstrate that serious games have a more positive impact on intrinsic motivation compared to extrinsic motivation.Serious games encompass comprehensive experiences that elicit internal stimuli related to goals, rules, and interaction for players (Deterding et al., 2011;Kim et al., 2018).
Notably, the features of intrinsic motivation, such as goals, rules, and interactions, align with the characteristics of serious games.Goals in games represent desired outcomes, such as rewards or positions, that players strive for (Kim et al., 2018), which resonates with the inherent satisfaction that fuels intrinsic motivation (Ryan & Deci, 2000a;2000b).Rules in games refer to the agreements or promises that govern gameplay (Kim et al., 2018), and they are linked to intrinsic motivation as they require the internalization of regulations (Ryan & Deci, 2000a;2000b).Interactions in games involve reciprocal actions and timely feedback, contributing to players' spontaneous enjoyment based on the balance between challenges and skills (Csikszentmihalyi, 2008;Kapp, 2012;Kim et al., 2018;Ryan & Deci, 2000a;2000b;Werbach & Hunter, 2012).
In general, the controllability of external conditions is in line with the partial and flexible designs of gamification, leading to significant effects on extrinsic motivation.Conversely, the internal stimuli from goals, rules, and interactions in serious games exhibit significant effects on intrinsic motivation.

Implications for designing Gamified Courses in Pedagogical Practices
Instructors should pay attention to the design of gamified courses based on the principles of gamification.Several influential factors, such as participants' emotional states, course integration, and adaptation, need to be considered (Aldemir et al., 2019).
The emotional states of participants play a crucial role in the design of gamified courses (Aldemir et al., 2019).Game designs should aim to stimulate participants' desired emotional responses (Hunicke, LeBlanc, & Zubek, 2004).At the beginning of gamified courses, cultivating curiosity is essential (Aldemir et al., 2019;Chou, 2015).Curiosity serves as the initial phase of discovery before the onboarding phase in gamified experiences (Chou, 2015).However, if participants do not understand the course content, their curiosity may not be fostered, leading to less satisfying learning experiences (Aldemir et al., 2019).Therefore, instructors should be aware of participants' interests and background information to facilitate effective curiosity (Aldemir et al., 2019).Conversely, negative emotional states of participants can still provide valuable guidance and support for the design of gamified courses to cater to their needs (Aldemir et al., 2019;Kapp, 2012).
In addition, gamified courses can integrate both online and in-class sessions (Aldemir et al., 2019;Keller, 2010).Both formats require flexibility, availability of materials, self-paced learning, social interactions, and direct interaction with instructors (Aldemir et al., 2019).Designing flexible courses that incorporate mental breaks and social rewards can help participants stay engaged and remain motivated to make progress (Werbach & Hunter, 2012).By understanding participants' learning preferences, instructors can use online platforms to deliver new knowledge and utilize class time to address specific problems through personalized guidance (Aldemir et al., 2019).It is important for educators to find a balance between the online and in-class sections to optimize efficiency based on participants' self-regulation (Aldemir et al., 2019).
Furthermore, participants' adaptation is crucial in gamified courses.Self-efficacy plays a significant role in determining participants' assigned roles within the gamified courses (Aldemir et al., 2019;Kapp, 2012).Participants with high self-efficacy tend to have a greater sense of confidence and actively engage in learning tasks (Kapp, 2012).As a result, the level of instructor control can decrease, but not disappear entirely.Therefore, participants need to adapt to a combination of freedom and control based on their self-regulation skills and technological competence (Aldemir et al., 2019;Kapp, 2012).

Key Findings
The first research question (RQ1) examines the effects of game-related approaches on learning achievement.The meta-analysis results indicate that game-related approaches, overall, have a positive impact on learning achievement (d = 0.480,z = 7.730,p < 0.05,95% CI [0.358,0.601]).Subgroup analysis reveals that the effect of gamification on learning achievement (d = 0.634,z = 5.911,p < 0.05,95% CI [0.424,0.844]) is more significant than that of serious games (d = 0.381,z = 5.214,p < 0.05,95% CI [0.238,0.524]).The regression analysis identifies Em (p < 0.05) and Cm (p < 0.05) as factors contributing to high heterogeneity, justifying the use of a random-effects model.Despite the absence of significant publication bias (p = 0.138 > 0.1), it can be concluded that gamification and serious games impact learning achievement differently, with gamification showing a more positive impact on learning achievement compared to serious games.
RQ3 aims to compare the effects of game-related approaches on intrinsic motivation versus extrinsic motivation.After categorizing the motivation-related concepts in the included studies, a subgroup analysis was conducted.The findings indicate that game-related approaches, on the whole, have a more positive impact on extrinsic motivation (d = 0.441, z = 3.206, p = 0.001 < 0.05, 95% CI [0.172, 0.711]) compared to intrinsic motivation (d = 0.403,z = 3.514,p < 0.05,95% CI [0.178,0.628]).Additionally, the effects of specific game-related approaches on intrinsic and extrinsic motivation were investigated.Serious games were found to have a more positive impact on intrinsic motivation (d = 0.352, z = 2.118, p = 0.034 < 0.05, 95% CI [0.026, 0.677]) than on extrinsic motivation (d = 0.205, z = 0.823, p = 0.411 > 0.05, 95% CI [-0.284, 0.695]).On the other hand, gamification exhibited a more positive effect on extrinsic motivation (d = 0.603,z = 4.374,p < 0.05,95% CI [0.333,0.873])than on intrinsic motivation (d = 0.481, z = 3.404, p < 0.05, 95% CI [0.204, 0.758]).The regression analysis revealed that the factors of approach (p = 0.012 < 0.05), Em (p < 0.05), and Cm (p < 0.05), which stemmed from experimental variations, contributed to the heterogeneity observed.These findings underscore the distinct effects of the two game-related approaches and support the use of a random-effects model.Moreover, no significant publication bias was detected (p = 0.353 > 0.1).In conclusion, game-related approaches have varying effects on intrinsic and extrinsic motivation.While overall they have a more positive impact on extrinsic motivation, serious games showed a stronger effect on intrinsic motivation, while gamification significantly enhanced extrinsic motivation.
We have also examined the potential factors that may explain these findings.Games that do not have specific educational objectives may offer more enjoyable and engaging experiences that capture learners' attention to the learning process.The presence of visible and controllable external stimuli, such as rewards, punishments, and leaderboards, may contribute to the significant effects of game-related approaches on extrinsic motivation.These findings suggest that instructors should pay attention to learners' emotional states, the integration of offline and online components, and the adaptation of both learners and instructors in gamified courses.
The main conclusions of this study are that gamification has a stronger positive impact on both learning achievement and motivation compared to serious games.Additionally, game-related approaches, overall, have a greater influence on enhancing extrinsic motivation rather than intrinsic motivation.It should be noted that serious games still have a more positive effect on intrinsic motivation compared to extrinsic motivation.

Limitations of this Study and Implications for Future Research
One major limitation of this study is the limited coverage of available studies.It is possible that we may have missed valuable findings due to the restricted availability of sources.We would greatly appreciate it if readers could contribute additional related studies to expand and diversify the results of this study.
Furthermore, the relatively high heterogeneity among the included studies is another limitation.Due to the variations in experimental procedures, we utilized random-effects models for the metaanalyses.However, reducing heterogeneity among the studies would minimize research errors and yield more persuasive results regarding the effects of game-related pedagogical models on learning achievement and motivation.
These limitations provide valuable insights for future research.Efforts should be made to broaden the coverage of research to address the heterogeneity issue.Future studies could specifically focus on comparing the effectiveness of serious game pedagogical models with gamification pedagogical models.Additionally, exploring other dimensions associated with the efficacy of game-related approaches would be beneficial.