Gamification for health and wellbeing: A systematic review of the literature

1The major health challenges facing the world today are shifting from traditional, pre-modern risks like malnutrition, poor water quality and indoor air pollution to challenges generated by the modern world itself. Today, the leading global risks for mortality and chronic diseases – high blood pressure, tobacco use, high blood glucose, physical inactivity, obesity, high cholesterol – are immediately linked to a modern lifestyle characterized by sedentary living, chronic stress, and high intake of energy-dense foods and recreational drugs. In addition, following calls from the World Health Organization's (2015/(1946) inclusive conception of health, researchers, civil society, and politicians have been pushing to extend policy goals from preventing and reducing disease towards promoting people's holistic physical, mental, and social well-being.

2Practically all modern lifestyle health risks (and resulting diseases) are directly affected by people's individual health behaviours — be it physical activity, diet, recreational drug use, medication adherence, or preventive and rehabilitative exercises. By one estimate, three quarters of all health care costs in the US are attributable to chronic diseases caused by poor health behaviours, the effective management of which again requires patients to change their behaviours. Similarly, research indicates that well-being can be significantly improved through small individual behaviours. Behaviour change has therefore become one of the most important and frequently targeted levers for reducing the burden of preventable disease and death and increasing well-being.

3A main factor driving behaviour change is the individual's motivation. Even if different theories contain different motivational constructs, “the processes that direct and energize behaviour” feature prominently across health behaviour change theories. Motives are a core target of a wide range of established behaviour change techniques.

4However, following self-determination theory (SDT), a well-established motivation theory, not all forms of motivation are equal. A crucial consideration is whether behaviour is intrinsically or extrinsically motivated. Intrinsic motivation describes activities done ‘for their own sake,’ which satisfy basic psychological needs for autonomy, competence, and relatedness, giving rise to the experience of volition, willingness, and enjoyment. Extrinsically motivated activity is done for an outcome separable from the activity itself, like rewards or punishments, which thwarts autonomy need satisfaction and gives rise to experiences of unwillingness, tension, and coercion. In recent years, SDT has become a key framework for health behaviour interventions and studies. A large number of studies have demonstrated advantages of intrinsic over extrinsic motivation with regard to health behaviours. Not only is intrinsically motivated behaviour change more sustainable than extrinsically motivated change: satisfying the psychological needs that intrinsically motivate behaviour also directly contributes to mental and social well-being.

5In short, in our modern life world, health and well-being strongly depend on the individual's health behaviours, motivation is a major factor of health behaviour change, and intrinsically motivated behaviour change is desirable as it is both sustained and directly contributes to well-being. This raises the immediate question what kind of interventions are best positioned to intrinsically motivate health behaviour change.

6The last two decades have seen the rapid ascent of computing technology for health behaviour change and well-being, with common labels like persuasive technology or positive computing. This includes a broad range of consumer applications for monitoring and managing one's own health and well-being, such as the recent slew of “quantified self” or “personal informatics” tools for collecting and reflecting on information about the self.

7One important sector is serious games for health, games used to drive health-related outcomes. The majority of these are “health behaviour change games” or “health games” affecting the health behaviours of health care receivers (and not e.g. training health care providers). Applications and research have mainly targeted physical activity, nutrition, and stroke rehabilitation, with an about equal share of (a) “exergames” or “active video games” directly requiring physical activity as input, (b) behavioural games focusing specific behaviours, (c) rehabilitation games guiding rehabilitative movements, and (d) educational games targeting belief and attitude change as a precondition to behaviour change. Like serious games in general, health games have seen rapid growth, with numerous systematic reviews assessing their effectiveness.

8A main rationale for using games for serious purposes like health is their ability to motivate: Games are systems purpose-built for enjoyment and engagement. Research has confirmed that well-designed games are enjoyable and engaging because playing them provides basic need satisfaction. Turning health communication or health behaviour change programs into games might thus be a good way to intrinsically motivate users to expose themselves to and continually engage with these programs (; though see ).

9However, the broad adoption of health games has faced major hurdles. One is their high cost of production and design complexity: Health games are typically bespoke interventions for a small target health behaviour and population, and game development is a cost- and time-intensive process, especially if one desires to compete with the degree of “polish” of professional, big studio entertainment games. Thus, there is no developed market and business model for health games, wherefore the entertainment game and the health industries have by and large not moved into the space.

10A second adoption hurdle is that most health games are delivered through a dedicated device like a game console, and require users to create committed spaces and times in their life for gameplay. This demand often clashes with people's varied access to technology, their daily routines and rituals, as well as busy and constantly shifting schedules.

11One possible way of overcoming these hurdles is presented by gamification, which is defined as “the use of game design elements in non-game contexts” (; see for a review). The underlying idea of gamification is to use the specific design features or “motivational affordances” of entertainment games in other systems to make engagement with these more motivating.1Appealing to established theories of intrinsic motivation, gamified systems commonly employ motivational features like immediate success feedback, continuous progress feedback, or goal-setting through interface elements like point scores, badges, levels, or challenges and competitions; relatedness support, social feedback, recognition, and comparison through leaderboards, teams, or communication functions; and autonomy support through customizable avatars and environments, user choice in goals and activities, or narratives providing emotional and value-based rationales for an activity (cf., ).

12Since its emergence around 2010, gamification has seen a groundswell of interest in industry and academia, easily outstripping persuasive technology in publication volume. By one estimate, the gamification market is poised to reach 2.8 billion US dollars by 2016. It is little wonder, then, that several scholars have pointed to health gamification as a promising new approach to health behaviour change. Popular examples are Nike+2, a system of activity trackers and applications that translate measured physical exertion into so-called “NikeFuel points” which then become enrolled in competitions with friends, the unlocking of achievements, or social sharing; Zombies, Run!3, a mobile application that motivates running through wrapping runs into an audio-delivered story of surviving a Zombie apocalypse; or SuperBetter4, a web platform that helps people achieve their health goals by building psychological resilience, breaking goals into smaller achievable tasks and wrapping these into layers of narrative and social support.

13Conceptually, health gamification sits at the intersection of persuasive technology, serious games, and personal informatics: Like persuasive technology, it revolves around the application of specific design principles or features that drive targeted behaviours and experiences. Several authors have in fact suggested that many game design elements can be mapped to established behaviour change techniques. Like serious games, gamification aims to drive these behaviours through the intrinsically motivating qualities of well-designed games. Like personal informatics, gamification usually revolves around the tracking of individual behaviours, only that these are then not only displayed to the user, but enrolled in some form of goal-setting and progress feedback. Indeed, many applications commonly classified as gamification are also labelled personal informatics, and gamification is seen as a way to sustain engagement with personal informatics applications (e.g., ).

14The reasons why gamification is potentially relevant to health behaviour change today, and the shortcomings of other digital health and well-being interventions include:Intrinsic motivation. Like games, gamified systems can intrinsically motivate the initiation and continued performance of health and well-being behaviours ( for similar arguments regarding gamification in general;,,; cf., ). In contrast, personal informatics can lack sustained appeal, and persuasive technologies often employ extrinsic motivators like social pressure or overt rewards.Broad accessibility through mobile technology and ubiquitous sensors. Activity trackers and mobile phones, equipped with powerful sensing, processing, storage, and display capacities, are excellent and widely available platforms to extend a game layer to everyday health behaviours, making gamified applications potentially more accessible than health games which rely on bespoke gaming devices.Broad appeal. As wider and wider audiences play games, games and game design elements become approachable and appealing to wider populations.Broad applicability. Current health gamification domains cover all major chronic health risks: physical activity, diet and weight management, medication adherence, rehabilitation, mental well-being, drug use, patient activation around chronic diseases like Diabetes, cancer, or asthma.Cost-benefit efficiency. Retro-fitting existing health systems and enhancing new ones with an engaging “game layer” may be faster, most cost-benefit efficient, and more scalable than the development of full-fledged health games.Everyday life fit. Gamified systems using mobile phones or activity trackers can encompass practically all trackable everyday activity, unlike health games requiring people to add dedicated time and space to their life. Whereas standard health games typically try to fit another additional activity into people's schedules, gamification aims to reorganise already-ongoing everyday conduct in a more well-being conducive manner (; see ).Supporting well-being. Beyond motivating health behaviours, engaging with gamified applications can directly contribute to well-being by generating positive experiences of basic psychological need satisfaction as well as other elements of well-being like positive emotions, engagement, relationships, meaning, and accomplishment (cf. for a review on well-being effects on video game play;, ).

15Intrinsic motivation. Like games, gamified systems can intrinsically motivate the initiation and continued performance of health and well-being behaviours ( for similar arguments regarding gamification in general;,,; cf., ). In contrast, personal informatics can lack sustained appeal, and persuasive technologies often employ extrinsic motivators like social pressure or overt rewards.

16Broad accessibility through mobile technology and ubiquitous sensors. Activity trackers and mobile phones, equipped with powerful sensing, processing, storage, and display capacities, are excellent and widely available platforms to extend a game layer to everyday health behaviours, making gamified applications potentially more accessible than health games which rely on bespoke gaming devices.

17Broad appeal. As wider and wider audiences play games, games and game design elements become approachable and appealing to wider populations.

18Broad applicability. Current health gamification domains cover all major chronic health risks: physical activity, diet and weight management, medication adherence, rehabilitation, mental well-being, drug use, patient activation around chronic diseases like Diabetes, cancer, or asthma.

19Cost-benefit efficiency. Retro-fitting existing health systems and enhancing new ones with an engaging “game layer” may be faster, most cost-benefit efficient, and more scalable than the development of full-fledged health games.

20Everyday life fit. Gamified systems using mobile phones or activity trackers can encompass practically all trackable everyday activity, unlike health games requiring people to add dedicated time and space to their life. Whereas standard health games typically try to fit another additional activity into people's schedules, gamification aims to reorganise already-ongoing everyday conduct in a more well-being conducive manner (; see ).

21Supporting well-being. Beyond motivating health behaviours, engaging with gamified applications can directly contribute to well-being by generating positive experiences of basic psychological need satisfaction as well as other elements of well-being like positive emotions, engagement, relationships, meaning, and accomplishment (cf. for a review on well-being effects on video game play;, ).

22In short, gamification may realize what games for health doyen Ben dubbed the “new model for health” games should pursue: sensor-based, data-driven, “seductive, ubiquitous, lifelong health interfaces” for well-being self-care.

23Promising as gamification for health and well-being may be, the essential question remains whether gamified interventions are effective in driving behaviour change, health, and well-being, and more specifically, whether they manage to do so via intrinsic motivation. These questions are especially relevant as (a) general-purpose literature reviews on gamification have flagged the lack of high-quality effect studies on gamification (; cf. ), and (b) critics have objected that gamification often effectively entails standard behavioural reinforcement techniques and reward systems that are extrinsically motivating, not emulating the intrinsically motivating features of well-designed games.

24To our knowledge, there is no systematic review on the effectiveness and quality of health and well-being gamification applications available. Existing reviews include a survey spanning several application domains which identified four health-related papers (cf. ), a review of gamification features in commercially available health and fitness applications, a topical review on the use of games, gamification, and virtual environments for diabetes self-management, which identified three studies on gamified applications, a review focused specifically on the use of (extrinsic) reward systems in health-related gamified applications and a review on the persuasion context of gamified health behaviour support systems. While these reviews offer important and valuable insights, none have examined gamification for both health and well-being nor the effectiveness of gamification. Additionally, existing reviews do not directly consider and evaluate the quality of evidence underlying the conclusions drawn. We therefore conducted a systematic literature review of peer-reviewed papers examining the effectiveness of gamified applications for health and well-being, assessing the quality of evidence provided by studies.

25We developed four guiding research questions:RQ1. What evidence is there for the effectiveness of gamification applied to health and wellbeing?What is the number and quality of available effect studies? This follows the observation that gamification research is lacking high-quality effect studies.What effects are reported? This follows the question whether health gamification is indeed effective.RQ2. How is gamification being applied to health and wellbeing applications?What game design elements are used and tested? These questions follow whether health gamification drives outcomes through the same processes of intrinsic motivation that make games engaging, and whether directly supporting well-being through positive experiences.What delivery platforms are used and tested? This probes whether current health gamification does make good on the promise of greater accessibility, pervasiveness, and everyday life fit through mobile phones or multiple platforms.Which theories of motivation (e.g., Self-Determination Theory) are used and tested? This explores to what extent health gamification explicitly draws on motivational theory and to whether design incorporating these theories leads to better outcomes.RQ3. What audiences are targeted? What effect differences between audiences are observed? These questions probe whether current applications indeed target a broad range of audiences with equal success., or whether they only target presumed gaming-affinitive audiences or show less success with non-gaming-affinitive audiences as well as whether.Is gamification shown to be more effective with gaming affinitive audiences? This assesses whether the benefits of gamification are limited to audience already familiar with or drawn to game elements as engaging and motivating.Have the benefits of health gamification been shown to extend to audiences that are not already intrinsically motivated? This explores whether there is evidence of gamification working when users are not already intrinsically motivated to perform the target activity (e.g., users who voluntarily engage with a fitness app can be assumed to already be intrinsically motivated to exercise).RQ4. What health and well-being domains are targeted? Beyond a general scoping of the field, this tests whether the claimed broad applicability of gamification indeed holds.

26RQ1. What evidence is there for the effectiveness of gamification applied to health and wellbeing?What is the number and quality of available effect studies? This follows the observation that gamification research is lacking high-quality effect studies.What effects are reported? This follows the question whether health gamification is indeed effective.

27What is the number and quality of available effect studies? This follows the observation that gamification research is lacking high-quality effect studies.

28What effects are reported? This follows the question whether health gamification is indeed effective.

29RQ2. How is gamification being applied to health and wellbeing applications?What game design elements are used and tested? These questions follow whether health gamification drives outcomes through the same processes of intrinsic motivation that make games engaging, and whether directly supporting well-being through positive experiences.What delivery platforms are used and tested? This probes whether current health gamification does make good on the promise of greater accessibility, pervasiveness, and everyday life fit through mobile phones or multiple platforms.Which theories of motivation (e.g., Self-Determination Theory) are used and tested? This explores to what extent health gamification explicitly draws on motivational theory and to whether design incorporating these theories leads to better outcomes.

30What game design elements are used and tested? These questions follow whether health gamification drives outcomes through the same processes of intrinsic motivation that make games engaging, and whether directly supporting well-being through positive experiences.

31What delivery platforms are used and tested? This probes whether current health gamification does make good on the promise of greater accessibility, pervasiveness, and everyday life fit through mobile phones or multiple platforms.

32Which theories of motivation (e.g., Self-Determination Theory) are used and tested? This explores to what extent health gamification explicitly draws on motivational theory and to whether design incorporating these theories leads to better outcomes.

33RQ3. What audiences are targeted? What effect differences between audiences are observed? These questions probe whether current applications indeed target a broad range of audiences with equal success., or whether they only target presumed gaming-affinitive audiences or show less success with non-gaming-affinitive audiences as well as whether.Is gamification shown to be more effective with gaming affinitive audiences? This assesses whether the benefits of gamification are limited to audience already familiar with or drawn to game elements as engaging and motivating.Have the benefits of health gamification been shown to extend to audiences that are not already intrinsically motivated? This explores whether there is evidence of gamification working when users are not already intrinsically motivated to perform the target activity (e.g., users who voluntarily engage with a fitness app can be assumed to already be intrinsically motivated to exercise).

34Is gamification shown to be more effective with gaming affinitive audiences? This assesses whether the benefits of gamification are limited to audience already familiar with or drawn to game elements as engaging and motivating.

35Have the benefits of health gamification been shown to extend to audiences that are not already intrinsically motivated? This explores whether there is evidence of gamification working when users are not already intrinsically motivated to perform the target activity (e.g., users who voluntarily engage with a fitness app can be assumed to already be intrinsically motivated to exercise).

36RQ4. What health and well-being domains are targeted? Beyond a general scoping of the field, this tests whether the claimed broad applicability of gamification indeed holds.

37The protocol for the review was developed and agreed by the authors prior to commencement. It followed all aspects recommended in the reporting of systematic reviews, namely the PRISMA Checklist and MOOSE Guidelines. All studies that explored the association between gamification and health were considered for this review. “Gamification” was defined and operationalised as “the use of game design elements in non-game contexts”. “Health” and “well-being” were collectively defined and operationalised using the inclusive definition of health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”.

38The electronic databases in this review were searched on November 19th, 2015 and included those identified as relevant to information technology, social science, psychology and health: Ebscohost (PsychInfo, Medline, CINAHL) (n = 33); ProQuest (n = 10); Association for Computing Machinery, ACM (n = 81); IEEE Xplore (n = 36); Web of Science (n = 44); Scopus (n = 108); Science Direct (n = 12) and PubMed (n = 39). Three additional studies were identified with a manual search of the reference lists of key studies, including existing gamification reviews, identified during the database search process.

39Based on prior practice in systematic reviews on gamification and health and well-being, we used full and truncated search terms capturing gamification, health outcomes, and well-being in the following search string:

40Gamif* AND (health OR mental OR anxi* OR depres* OR wellbeing OR well-being).

41Mental health related search terms (“mental”, “anxi*” and “depres*”) were added as initial searches failed to capture some expected results.

42Our review focused on high quality scholarly work reporting original research on the impact and effectiveness of gamification for health and wellbeing. From this focus, we developed the following inclusion criteria:Peer-reviewed (incl. peer-reviewed conference papers)Full papers (incl. full conference papers)Empirical research (qualitative and quantitative)Explained research methodsExplicitly state and described gamification as research subjectClearly described gamification elements (type of game design elements)Effect reported in terms of:Impact (affect, behaviour, cognition), and/orUser experience — any subjective measure of experience while using the gamified or non-gamified version of the interventionClearly described outcomes related to health and well-being

43Peer-reviewed (incl. peer-reviewed conference papers)

44Full papers (incl. full conference papers)

45Empirical research (qualitative and quantitative)

46Explained research methods

47Explicitly state and described gamification as research subject

48Clearly described gamification elements (type of game design elements)

49Effect reported in terms of:

50Impact (affect, behaviour, cognition), and/or

51User experience — any subjective measure of experience while using the gamified or non-gamified version of the intervention

52Clearly described outcomes related to health and well-being

53Criteria 1–4 were chosen to ensure focus on high-quality work reporting original research. Criteria 3, 4, and 7 were also included to enable assessment of quality of evidence. Criteria 5–6 ensured the paper reported on gamification, not serious games or persuasive technology mislabeled as gamification (a common issue, cf. ). Criteria 7–8 were chosen to assess reported health and well-being outcomes and potential mediators, with user experience included given its prevalence as an outcome measure in gamification research (see Table 1).

54Our exclusion criteria mirror the focus on high quality scholarly work that reports the impact and effectiveness of gamification for health and well-being. They were particularly framed to exclude duplicate reporting of earlier versions of studies fully reported later. We excluded papers with the following features:Extended abstracts or ‘work-in-progress’ papersStudy protocolsCovers complete games (serious games) not gamificationGamification is mentioned but not evaluated

55Extended abstracts or ‘work-in-progress’ papers

56Study protocols

57Covers complete games (serious games) not gamification

58Gamification is mentioned but not evaluated

59Criteria 1–2 exclude peer-reviewed yet early and incomplete versions of studies. Criteria 3–4 exclude studies that mislabel serious games as gamification (see above) or fail to report the concrete intervention in sufficient detail to assess whether it constituted gamification.

60We used the quality assessment method presented by. The tool was explicitly developed to assess the strength of evidence of a total body of work relative to a particular review question. used the tool to assess the overall weight of empirical evidence for positive impact and outcomes of games. We applied the tool to our more focused interest in the empirical evidence for the effectiveness of gamification in the health and wellbeing domain. Each final paper included in the review was read and given a score of 1–3 (where 3 denotes high, 2 denotes medium and 1 denotes low on that criterion) across the following five criteria:How appropriate is the research design for addressing the research questions of this review (higher weighting for inclusion of a control group)High — 3 RCTMedium — 2, quasi-experimental controlled studyLow — 1, case study, single subject-experimental, pre-test/post-test designHow appropriate are the methods and analysis?How generalizable are the findings of this study to the target population with respect to the size and representativeness of the sample? To what extent would the findings be relevant across age groups, gender, ethnicity, etc.How relevant is the particular focus of the study (incl. Conceptual focus, context, sample and measure) for addressing the question of this review?To what extent can the study findings be trusted in answering the study question?

61How appropriate is the research design for addressing the research questions of this review (higher weighting for inclusion of a control group)

62High — 3 RCT

63Medium — 2, quasi-experimental controlled study

64Low — 1, case study, single subject-experimental, pre-test/post-test design

65How appropriate are the methods and analysis?

66How generalizable are the findings of this study to the target population with respect to the size and representativeness of the sample? To what extent would the findings be relevant across age groups, gender, ethnicity, etc.

67How relevant is the particular focus of the study (incl. Conceptual focus, context, sample and measure) for addressing the question of this review?

68To what extent can the study findings be trusted in answering the study question?

69The total weight of evidence for each paper is calculated by adding the scores of all five dimensions, with a range from 5 to 15. analysis of the empirical evidence regarding games and serious games found a mean rating of 8.56 and a mode of 9, which gave us a baseline to evaluate gamification studies against. Connolly et al. (ibid.) found 70 of 129 or 54% of studies to be above the mode, constituting “stronger evidence”. We elected to categorise in slightly more detail, with papers with a rating 8 or below categorised as “weaker evidence”, papers with a rating above 8 to 12 as “moderate evidence”, and papers with a rating above 12 as “stronger evidence”.

70Based on an initial survey, we categorised delivery modalities as mobile (phone), website, social network application, analog, or bespoke device. Given the lack of consensus in the literature regarding definitions and categorizations, game design elements were coded using an adaptation of the systemisation provided by. Hamari and colleagues identified the following typology: points, leaderboards, achievements/badges, levels, story/theme, clear goals, feedback, rewards, progress and challenge. In the current review, we elected to combine points and badges with other digital rewards (e.g., virtual roses, coins, digital in-app equipment) into a single category labelled ‘rewards’. Additionally, we also coded for the inclusion of an ‘avatar’ or ‘social interaction,’ as these were found to be commonly employed game design elements in the reviewed papers.

71We categorised health and well-being effects as relating to affect (mood), behaviour (i.e., involving real world actions), or cognition (e.g., sense of empowerment, motivation, stress, knowledge of domain). These categories were chosen based on the three-component model of attitudes with the primary adaptation being the inclusion of knowledge of the target domain as part of the cognition category (knowledge was only assessed in one study. In addition, multiple studies also assessed user experience (e.g. attitudes towards the gamified intervention itself), which we coded separately. Furthermore, we coded effects as positive, negative, or mixed/neutral, the latter meaning that results were inconclusive or positive for one group and negative for another. If a study assessed health and well-being impacts for multiple dimensions, these were counted separately. For example, a study that finds positive effects on stress and life satisfaction would be counted as two positive impacts on cognition. In contrast, a study that finds a positive impact on life satisfaction for one group of users and negative impact for another would be coded as one neutral/mixed impact on cognition.

72All studies were independently coded by a second reviewer. Inter-rater reliability was determined by the intra-class correlation coefficient (ICC). This statistic allows for the appropriate calculation of weighted values of rater agreement and accounts for proximity, rather than equality of ratings. A two-way mixed effects, average measures model with absolute agreement was utilized. Independent ratings demonstrated an excellent level of inter-rater reliability (2-way mixed ICC = 0.91; 95% CI 0.77–0.96).

73Our search identified 365 papers. After removing duplicates 221 papers remained. Of these 191 were removed based on screening of title and abstract. The remaining 30 articles were considered and assessed as full texts. Of them eleven did not pass the inclusion and exclusion criteria. Nineteen final eligible studies remained and were individually assessed for this review. The study selection process is reported as recommended by the PRISMA group in Fig. 1.

74The final 19 articles eligible for review were then rated for quality of evidence (in relation to the current papers review question, see Table 1). Following we calculated the mean (10.3) and mode (10.5) as a means of determining which papers provided relatively weaker or stronger evidence. However, we departed from the approach taken by Connolly and colleagues who assigned papers to two categories (weaker and stronger quality of evidence) and instead categorised papers into three categories (weaker, moderate and stronger evidence). This decision was made as an equal number of papers fell above and below the mode of 10.5 (also the median), which in turn meant that classifying papers with the modal/median score as either weaker or stronger evidence arbitrarily resulted in that category appearing as a majority. Based on this, 8 papers (42%) were categorised as providing weaker evidence, 3 papers (16%) were categorised as providing moderate evidence and 8 papers (42%) were categorised as providing stronger evidence. See Fig. 2 for a histogram displaying quality of evidence ratings.

75A closer look into methodologies helps unpack these ratings. The majority (n = 11) of studies collected data at multiple timepoints (two or more) from multiple groups or conditions; 6 studies collected data from a single group at multiple timepoints, two from a single group at a single time point. Notably, more than half (n = 10) of the studies did not compare gamified and non-gamified versions of the interventions studied. Sample sizes ranged from 5 to 251, sampling methods included both convenient and systematic.

76Chief modalities employed were mobile applications (n = 7) and websites (n = 6), with several studies offering an intervention across both. Two studies each used analog techniques, social networking sites, or bespoke devices, namely a modified fork and a Wii console and Wii Fit board. Game design elements included avatars, challenges, feedback, leaderboards, levels, progress indicators, rewards and story/theme and social interaction (see Table 2). A total of 46 instances of implemented gamification elements were found across the 19 papers. The most commonly employed elements were rewards (n = 16), leaderboards (n = 6) and avatars (n = 6).

77There was a broad variety without discernible patterns in outcome measures (including surveys/questionnaires, interviews, diary entries, videos, log files and equipment readings such as blood glucose readings), target audiences, or contexts, including medical settings, home recovery, self-assessment, health monitoring, stress management, improving eating behaviours, and increasing physical activity.

78Overall (see Table 3), positive effects of gamified interventions were reported in the majority of cases (n = 22, 59%), with a significant proportion of neutral or mixed effects (n = 15, 41%) and no purely negative effects reported. The majority of assessed outcomes were behavioural (n = 19, 51%) or cognitive (n = 17, 46%). Affect was rarely assessed (n = 1, 3%).

79Beyond health and well-being impacts, 12 studies assessed user experience impacts, with 5 (42%) reporting positive, 5 (42%) reporting mixed and 2 (16%) reporting negative impacts.

80For the most part, gamification has been well received; it has been shown to foster positive impacts on affect, behaviour, cognition and user experience. The majority of studies reported gamification had a positive influence on health and well-being. In those cases where gamification had mixed or negative effects, the primary issues seemed to be: 1) the context in which gamification was used (e.g., mindfulness), 2) the manner in which gamification was applied (e.g., exaggerated feedback), or 3) a mismatch between the gamification techniques used and the target audience (e.g., non-beginners feeling that gamification interfered with access to the target activities).

81We assessed evidence based on the number, quality and the reported effects of available studies. We identified a total of 19 studies assessing the effects of gamified health and wellbeing interventions published since 2012 (avg. 5 studies/year). The most comparable serious games for health meta-analysis in terms of inclusion and exclusion criteria is, which found 53 studies published between 1989 and 2013 (avg. 2 studies/year). This provides evidence that health gamification research like gamification research in general is progressing at a fast pace (cf. ).

82Quality of evidence ratings of existing research conducted by two raters, indicated an equal number of papers were of weak (n = 8) or strong (n = 8) quality, and the remainder (n = 3) were of moderate quality. This suggests that health and wellbeing research is approximately in line with the low evidence quality of gamification research in general (cf., ) or perhaps slightly better. It is also consistent with the quality of research found in (serious) game research in general: our study found a mean quality rating of 10.3 (with 42% of papers below the mean and classified as providing weaker evidence). In comparison, reported a mean rating of 8.56 (with 46% of papers classified as providing weaker evidence). While the number of studies included in the current review precludes any firm conclusions, the slightly higher mean quality score found in the current study could indicate the quality of evidence for empirical effectiveness is slightly higher in gamification in health and wellbeing than the broader serious games literature. More broadly, it is worth noting that the small number and low quality ratings of studies included in this review reflect the relative infancy of the gamification field and the formative nature of research conducted to date.

83It should also be noted that this analysis of quality of evidence is not intended as a critique of the peer review the selected papers underwent. The papers were categorised as providing lower, moderate or stronger evidence solely with respect to the weight of empirical evidence for health and well-being effects; studies may well be considered differently based on other aims and criteria.

84The impact of gamified interventions on health and well-being was found to be predominantly positive (59%). However, a significant portion (41%) of studies reported mixed or neutral effects. More specifically, findings were largely positive for behavioural impacts (13 positive, 6 mixed or neutral), whereas the evidence for cognitive outcomes is less clear-cut, with an approximately equal number of reported positive (n = 8) and mixed/neutral (n = 9) impacts. Notably, no direct negative impacts on health and wellbeing were reported, although 2 of 12 studies that additionally assessed user experience reported negative impacts on the latter. This picture is more positive than comparable general gamification reviews (cf., ). Current results suggest gamification of health and wellbeing interventions can lead to positive impacts, particularly for behaviours, and is unlikely to produce negative impacts. That being said, gamification should be used with caution when the user experience is critical, e.g. where users can voluntarily opt in and out of the intervention. For example, documented user complaints about the poor usability of gamified running apps, which resulted in individual users ceasing to use them. similarly suggest that gamification may detract from usability and user experience by adding task demands to the interface.

85The majority of papers (n = 7) explored mobile devices or websites as the delivery platform (n = 6). Positive effects were also found outside the digital domain including a gamified physical display in the classroom and a sensor-equipped fork designed to influence children's eating habits. This is in line with the identified promises of everyday life fit and broad accessibility of gamification through mobile and ubiquitous sensor technology. That being said, there are few studies directly testing the differences and effects of everyday life fit and accessibility in mobile/ubiquitous versus PC/bespoke device-based interventions. found no difference in effectiveness between a web-based and mobile gamified cognitive bias modification training for alcohol use, but did not explicitly design and control for everyday life fit and accessibility as independent variables.

86Although the assessed studies included a broad range of game design elements, there was a clear focus on rewards, constituting 16 of a total of 46 instantiations of game design elements across studies (35%), followed by leaderboards and avatars (6 instantiations or 13% each). A notable 84% of all individual studies involved rewards in some form (16 out of 19 studies). Not a single included study captured effects of game design elements on intrinsic motivation as a direct outcome (e.g. motivation to exercise) or mediator for other health and wellbeing outcomes. Taken together with the fact that the majority of studies focused purely behavioural outcomes (see above), this indicates that the dominant theoretical and practical logic of the studied health and wellbeing gamification interventions is positive reinforcement. In other words, the promise of intrinsically motivating health behaviour by taking learnings from game design is currently neither explored nor tested.

87Eighteen of the 19 included studies implemented multiple game elements, and no study tested for the independent effects of individual elements. This makes it difficult to attribute effects clearly to individual game elements, and again underlines the need for more rigorously designed studies. With this caveat, the strongest evidence available does support that rewards5 drive health behaviours: found rewards in the form of points and achievements to be associated with improvements in desire to exercise. saw points (in combination with leaderboards) to contribute significantly to increased physical activity. similarly found that rewards (badges and points) and leaderboards led to an increase in physical activity among dyads working cooperatively (or working in a hybrid cooperative/competitive mode), but not among dyads working competitively. found that rewards (points, badges and medals in combination with leaderboards) were associated with increased physical activity and sense of empowerment as well as decreased health care utilization among Rheumatoid Arthritis patients. saw rewards (in the form of points that could be redeemed for prizes) to contribute to the frequency of blood glucose measurement among individuals with type 1 diabetes. similarly found a positive impact of points (with leaderboards) on outcomes related to chronic back pain, including reduced medication misuse, lowered pain burden, and increased exercise. With a group of highly trait-anxious participants, found rewards (in the form of points) associated with reduced subjective anxiety and stress reactivity.

88In contrast to these positive outcomes, report mixed results: rewards (in combination with leaderboards) led to a short-term (8 week follow-up) increase in moderate to vigorous physical activity, but no long-term effects (20 week follow-up). Similarly, they found no impact of gamification on self-reported general or mental quality of life. Studying a mobile application designed to increase routine walking, similarly found no differences between gamified (points and leaderboards) and non-gamified versions. Relatedly, in a qualitative study of gamified mobile running applications, observed poor usability of gamified applications leading to users stopping to use them.

89Avatars are commonly employed as a gamification technique to represent the user in the application context. Again, the majority of studies found avatars were associated with positive outcomes. developed an application with an avatar that ‘grew stronger’ the longer users were standing instead of sitting on public transport. They found evidence for increased motivation to stand. compared a gamified mobile attention-bias modification training for anxiety using virtual characters with a placebo training and found it to significantly reduce subjective anxiety and stress reactivity. In a series of two studies,, found that avatars (in combination with rewards, levels and narrative) led to increased fruit and vegetable consumption among children. Assessing the effectiveness of a gamified (avatar and backstory) application designed to moderate alcohol use, observed a positive impact on motivation to train; however, participants reported greater task demand associated with the gamified version of the application.

90Social Interaction was also commonly employed as a means to engage users and was found to increase user experiences of fun and motivation in the context of moderating alcohol consumption, to have a positive influence on physical activity (Juho,, ) and flourishing mental health. Less commonly employed gamed design elements across studies included levels (; Juho,, ), progress, story/theme, challenges and feedback.

91With respect to theories of motivation, very few studies provide insight regarding the extent to which gamification that draws on relevant theory is more effective. Only a minority of studies (n = 8) explicitly discuss motivational theory and very few studies (n = 3) are conducted in a manner that assesses whether a motivational construct is associated with positive outcomes. Most commonly, self-determination theory and intrinsic/extrinsic motivation were the theories discussed in relation to health gamification (; Juho,,, ). Other theories (relevant to motivation) that were considered include design strategies to reduce attrition and guides for behaviour change, empowerment and the transtheoretical model of behaviour change.

92As discussed above, most studies considered multiple gamification elements simultaneously making it difficult to isolate the effects of individual elements. In some cases, this also makes it more difficult to consider the impact of specific theories of motivation. found a positive impact of social norms and recognition providing support for self-determination theory in terms of relatedness of social influence. Similarly, although mixed evidence was found for the impact of the gamification elements used, interpret their results as confirming the value of concept of ‘meaningful’ gamification and the self-determination driven ideas of informational feedback and customizable elements. Further affirming the notion of ‘meaningful’ gamification, discuss how their findings highlight the importance of meaningful experiences rather than rewards.

93A broad range of audiences were targeted throughout the research reviewed. While some studies focussed on younger participants (ranging from Kindergarten age to adolescents, the majority of studies were conducted with adults. Regardless, positive outcomes have been found for children, adolescents and young adults.A small number of studies focussed on specific audiences, such primary school teachers, participants with specific health issues like chronic back pain, rheumatoid arthritis, or high levels of trait anxiety. It is not immediately clear from the reviewed studies what relationship exists between existing gaming affinity or expertise and the effectiveness of gamification as previous experience with digital games is not commonly reported.

94Beyond demographics, factors relevant to the potential effectiveness of gamification seem to include the users' personality, as well as their level of knowledge, expertise, abilities, and basic motivation to engage in the target activity initially. In a study where 15 first-time Wii Fit users were asked to use a Wii balance board to increase their fitness, findings about the effectiveness of gamification were mixed. Only beginners responded positively to gamified elements incorporated into the exercise activities, while these same features had a negative effect on experienced fitness users, leading them to abandon the system as a fitness tool. Non-beginners reported that gamified features slowed down the pace of the exercise, leading to their disengagement, and feedback was disliked, as praising was considered exaggerated.

95Importantly, the studies reviewed suggest that the benefits of health gamification extend beyond audiences who have pre-existing motivations to engage in the target activity. Although many (n = 11) of the studies involved participants who were likely to have pre-existing motivation, of the studies conducted with participants without existing motivations (n = 8), the majority (n = 7) showed some positive results. Positive impacts of gamification were found with young children around eating behaviours; university students regarding alcohol consumption; commuters with respect to standing and teachers in relation to positive psychology training. Furthermore, when comparing beginners and experts, Reynolds and colleagues found positive impacts of gamification on exercise behaviour only for the beginners (who are presumably less intrinsically motivated than experts).

96Across fields, the most popular and successful context for the application of gamification is physical health (n = 13) and more specifically, its use for motivating individuals to increase their physical activity, or to engage in self-monitoring of fitness levels (n = 10). Notably, a positive impact of gamification on physical activity related outcomes are observed in 8 of the 10 studies with mixed effects observed by and.

97Motivation to exercise is increased largely through “fun” activities, through cooperating, competing, and sharing a common goal with peers or exercise buddies (e.g., ), or through various other social incentives (e.g., ). There is evidence that gamification features may be more motivating than exercise alone. Some elements can stimulate increased exercise and reduce physical fatigue (. Gamifying fitness is a way to attract users, encourage participation and motivate behaviour change. There is also evidence to suggest that social influence may play a key role in the influence of gamification on willingness to exercise (Juho ). While gamified elements can provide motivation to maintain or increase physical activity, such outcomes may not be sustained over time; these responses are not necessarily consistent for all types of users; and not all types of elements help users achieve their fitness goals or positively impact user adoption. Nevertheless, these studies combined lend support to the use of gamification as a viable intervention strategy in fitness contexts. Outside of activity, within the domain of physical health a positive influence of gamification was also found in three studies of nutrition.

98The remaining studies exploring the impact of gamification within the domain of physical health examined illness related issues. Gamification was found to have a positive influence on healthcare utilization, the reduction of medication misuse and blood glucose monitoring. In two studies these changes were also associated with a positive influence on patient empowerment.

99In the domain of mental health, gamification has been shown to have positive effects on wellbeing, personal growth and flourishing as well as stress and anxiety. This supports the identified promise of gamification to directly support wellbeing. More mixed results were found with respect to substance use, with evidence of an increased motivation to train with a gamified version of a tool (designed to alter positive associations with alcohol in memory), alongside evidence of lowered ease of use. However, in a study of mental wellness training, which involved concentration, relaxation and other techniques to encourage changes in thoughts and negative beliefs, gamification was received with skepticism by just over half of the users. Participants suggested that points, rewards and achievements were a poor fit in the context of mental wellness and mindfulness. However, it is not clear to what extent this point of view is related to the specific types of gamification used in the study and whether the finding would extend to a broader sample.

100As noted throughout the discussion, the small number and wide variability in the design, quality and health behaviour targets of the gamification studies included in this review limits the conclusions which can be made. There is a need for more well-designed studies comparing gamified and non-gamified interventions: we need randomized controlled trials and double-blind experiments that tease out the effect of individual game design elements on mediators like user experience or motivation and health and wellbeing outcomes, with adequately powered sample sizes, control groups and long-term follow up assessments of outcomes. The studies included in this review typically conflated the assessment of multiple game design elements at once, often involved small sample sizes, did not feature control groups, or only focused on user experience outcomes. Additionally, very few studies have explored the long-term or sustained effects of gamified products, which means that current support for gamification may in part reflect its novelty.

101Finally, the heuristic used (positive, negative, neutral) in the current review to evaluate impact, was considered appropriate given the heterogeneity of included studies. However, once more studies on individual gaming elements are completed, future reviews should consider using a more complex heuristic to evaluate impact.

102As the main contributors to health and wellbeing have shifted towards personal health behaviours, policymakers and health care providers are increasingly looking for interventions that motivate positive health behaviour change, particularly interventions leveraging the capabilities of computing technology. Compared to existing approaches like serious games for health or persuasive technology, gamification has been framed as a promising new alternative that embodies a “new model for health”: “seductive, ubiquitous, lifelong health interfaces” for well-being self-care. More specifically, proponents of gamification for health and wellbeing have highlighted seven potential advantages of gamification: (1) supporting intrinsic motivation (as games have been shown to motivate intrinsically), (2) broad accessibility through mobile technology and ubiquitous sensors, (3) broad appeal across audiences (as gaming has become mainstream), (4) broad applicability across health and wellbeing risks and factors, (5) cost-benefit efficiency of enhancing existing systems (versus building bespoke games), (6) everyday life fit (reorganising existing activity rather than adding additional demands to people's lives), (7) direct wellbeing support (by providing positive experiences).

103That being said, little is known whether and how effectively gamification can drive positive health and wellbeing outcomes, let alone deliver on these promises. In response, we conducted a systematic literature review, identifying 19 papers that report empirical evidence on the effect of gamification on health and wellbeing. Just over half (59%) of the studies reported positive effects, whereas 41% reported mixed or neutral effects. This suggests that gamification could have a positive effect on health and wellbeing, especially when applied in a skilled way. The evidence is strongest for the use of gamification to target behavioural outcomes, particularly physical activity, and weakest for its impact on cognitions. There is also initial support for gamification as a tool to support other physical health related outcomes including nutrition and medication use as well as mental health outcomes including wellbeing, personal growth, flourishing, stress and anxiety. However, evidence for the impact of gamification on the user experience, was mixed. Further research that isolates the impacts of gamification (e.g., randomized controlled trials) is needed to determine its effectiveness in the health and wellbeing domain.

104In terms of the highlighted promises, little can be said conclusively. No intervention examined intrinsic motivation support (1), as the majority of studies subscribed to a behaviorist reinforcement paradigm. Most studies did employ mobile and/or ubiquitous technology (2), yet no study directly assessed whether they differed in accessibility compared to stationary delivery modes. The range of participant samples employed across studies suggests likely broad appeal across audiences (3) and the wide range of health and wellbeing issues addressed across studies does support broad applicability (4) in principle. None of the studies included assessed cost-benefit efficiency (5) or everyday life fit (6). On a positive note, multiple studies found evidence that gamified interventions did directly support participants' wellbeing (7).