Leadership and Sustainable Innovation: A Systematic Literature Review

Abstract

This study aims to systematically review and analyze effective leadership and sustainable innovation. The present study incorporated different research designs and the review were based on the published standard, namely PRISMA statement (Preferred Reporting Items for Systematic Reviews and thematic Analysis). This study has considered 80 related studies using Scopus as the primary database for this systematic literature review. Three key themes emerged from a closer examination of these articles: innovativeness, innovation performance, and innovative behavior at work. Transformational leadership was the style of leadership that received the most attention. Leader’s innovative strategies and subordinate’s innovative task performance were mostly associated with overall performance in achieving sustainability. The authors of 31 of the 80 publications included empirical research. In most of the earlier research, social exchange theory and resource-based view theory have been utilized. The authors of the studies included in this study’s synopsis of how leadership affects sustainable innovation did not reach a consensus on their empirical findings. This comprehensive evaluation of the literature also includes several restrictions and suggestions for the way forward.

1. Introduction

Leadership is one of the most important phenomena in management research and practice, leading to a large body of theoretical and empirical work [1, 2]. Their impact on their organizations’ performance cannot be overstated. Leaders are responsible for their organization’s success and failure. Influencing others is leadership [3]. Leadership is a major factor in employee performance [4, 5]. Leadership stimulates employee innovation and inventive work behavior [6, 7]. Organizations are focused on refining their current processes and offers and strengthening and sustaining their market position [8]. In tough circumstances, organizations must innovate and adjust procedures to boost innovation performance [9]. Leadership is a key predictor of organizational innovation and the level of innovation support in an organization.

Each organization’s development and present operation are dependent on the traits of its leaders. In addition to having a clear vision and effectively communicating it, managers of organizations need to have people-motivating abilities. It is evident that effective leadership is required [10]. However, over time, the definition of “suitable leadership” has evolved [11]. The way organizations should be managed is being impacted by changes in the business environment, including new stakeholder needs. The global shift toward sustainability is another example of such a development [12]. Traditional leadership was only focused on making money, and conventional conceptions of development—which persisted until the 1970s—evaluated development within the context of economic expansion [13]. The three interconnected pillars of sustainable innovation, innovativeness and organizational innovation performance must be balanced by current leaders [14].

This chapter explores many articles that discuss leadership styles and organizational innovation to better understand this link and draw a unique conclusion. This analysis will assist organizations and decision-makers choose the best leadership style to boost innovation and get a market edge. According to Amundsen et al. [15] “Leader support” is the most critical requirement for innovation success. Arshad et al. [6] say management support drives innovation for two reasons. First, employee participation in strategic innovation decision-making requires managerial backing. Second, it could mean coaching employee initiatives during ideation and decision-making. Smith et al. [16] identified leader support as a critical antecedent of creativity and innovation, saying that management behavior and creativity demand more attention. Studies have shown that subordinates need leadership support to innovate [17, 18]. Despite our theoretical grasp of leadership’s impact on innovation, we lack a comprehensive understanding of how specific leadership styles might encourage or hinder sustainable innovation. Smith et al. [16] propose a favorable influence of leader support on creativity and innovation. However, different leadership styles have varied benefits and drawbacks [19]. How will leadership styles affect sustainable innovation?

This chapter examines how leadership styles affect innovation among leaders and subordinates. Which style delegated authority to subordinates? [15, 20]. The innovation described above presents some traits of a suitable leadership approach under the context of current business operations. Although some authors (e.g., [21, 22, 23, 24]) emphasized that transformational leadership contributes to broadly defined sustainable innovation by influencing responsible practices and behaviors, others (e.g., [25]) explored the benefits of servant leadership. Others have written about sustainable leadership, such as Avery and Bergsteiner [26] and Iqbal et al. [27]. Sustainable leadership is a marginalized and underdeveloped topic, according to a literature analysis on the effectiveness of sustainable human resource management done by Santana and Lopez-Cabrales [28]. According to Kjellström et al. [11], leadership in general is a complex phenomenon that requires further investigation. The purpose of this study is to identify and explore the leadership styles (types) that positively influence the performance of sustainable innovation, both numerically and qualitatively. This will further the field of “leadership-sustainable innovation” research by analyzing, contrasting, and synthesizing earlier findings [29]. For the purpose of this study, the following research questions were formulated: We studied these competing leadership styles because of their clashing qualities. We answer these questions.

RQ1: Which leadership style best fosters sustainable innovation?

RQ2: Which leadership theory is most helpful for creativity by leaders and subordinates?

RQ3. Future study on leadership and sustainable innovation?

By concentrating on the implications of recent work on innovation for sustainability and leadership styles in the service industries, the current study fills in these gaps. In contrast to earlier review studies, this study highlights the key themes in the various leadership innovations and styles that have been described in the literature. We do this by offering several taxonomies, summarizing recent research, and perhaps moving academic efforts away from pure inquiry and toward a more methodical approach. To conduct a comprehensive thematic analysis of the existing literature, it uses both quantitative and qualitative methodologies. The results are used to identify what is now known about sustainable innovation and what needs further study from a leadership viewpoint. The study starts off by providing a summary of current leadership research before zeroing in on the literature on innovation. The chosen technique is presented in the following parts, together with a thorough analysis of the findings, conclusions, and suggestions for further study.

2. Materials and methods

2.1 Prisma

Based on pertinent PRISMA, or Preferred Reporting Items for Systematic Reviews and thematic Analyses, guidelines, a systematic review was created. The PRISMA guidelines were created to aid researchers in enhancing the reporting of systematic reviews and to prevent a number of writing errors that could be misunderstood and result in unintentional bias [30, 31]. PRISMA is also appropriate for the management field [32].

2.2 Resources

Scopus was used to conduct a search of publications’ electronic literature. The primary database used for the review is Scopus. Physical sciences, social sciences, health sciences, and biological sciences are only a few of the many disciplines covered by Scopus. Data may be easily seen, compared, and exported thanks to Scopus analytics tools.

2.3 Systematic review process

Identification, screening, and eligibility are the three key phases in a systematic review of the literature (refer to Figure 1).

Figure 1.

Flow chart of sample.

2.4 Identification

The keywords to be used in the search procedure were determined in the first phase. Identification is the process of looking up every possible synonym, phrase connected to it, and variation for the study’s primary keywords. It seeks to provide the chosen database with extra possibilities for looking up additional relevant articles to review. The study topic as proposed by Okoli [33] served as the basis for the development of the keywords, which were then identified using an online thesaurus, keywords from previous studies, keywords from Scopus, and keywords recommended by experts. On the main database, Scopus, the authors were able to expand upon the already existing keywords and create a comprehensive search string based on Boolean operators, phrase searching, truncation, wild cards, and Field code operations. After choosing all the appropriate keywords. A total of 1822 articles from Scopus were successfully retrieved for the present research project.

2.5 Screening

The screening came in at stage two. The goal of the initial screening stage was to eliminate duplicate articles and excluded articles non-English, in this stage total number of excluded papers was 116, and included studies was 1706. In this instance, some articles were eliminated during the initial screening stage, 297 papers were excluded, and 1409 articles were then screened using the inclusions listed below.

2.6 Exclusion criteria

Due to its role as the principal source of empirical data, the journal (research papers) was the only genre of writing that received attention. The current study, therefore, does not include any systematic reviews, reviews, meta-analyses, meta-syntheses, book series, novels, book chapters, or conference proceedings so the study excluded 572 papers in this stage. The review was restricted to leadership in the field of management. Due to their alignment with the review’s goal, only studies on business management were chosen. 837 articles are currently eligible for evaluation.

2.7 Eligibility

The entire article was accessed in the eligibility stage, which was the third step. The third step, eligibility, involves the writers manually checking the returned articles to make sure all the ones still there (after the screening procedure) meet the requirements. Reading the articles’ titles and abstracts served as the first step in this approach we excluded 733 studies and included only 104 studies. There were just 80 items that were chosen overall that study fully utilized for further analysis (see Figure 1).

3. Results and discussion

3.1 Data abstraction and analysis

Assessment and analysis were done on the remaining publications. Focused efforts were made on research that provided answers to the posed questions. To extract the data, the abstracts and entire papers were thoroughly examined before identifying the pertinent topics and sub-themes. Whittemore and Knafl [34] claim that adopting qualitative or mixed-method techniques that allow the researcher to make ongoing comparisons across primary data sources is the best way to synthesize or evaluate integrative data. To find themes relating to leaders’ innovation, qualitative analysis utilizing content analysis was conducted. All 80 publications have undergone in-depth analysis, especially in the abstract, results, and discussion parts. The research questions served as the basis for the data abstraction, which means that all information from the examined studies that could help answer the research questions was taken out and put into a table. The researcher then carried out a thematic analysis to find themes and sub-themes based on observations of patterns and themes, creativity, innovativeness, creative work behavior, and connections that existed within the abstracted data [35].

Generating themes is the first stage in a thematic analysis. The patterns that developed from the abstracted data of all reviewed publications must be recognized during this procedure. The authors reexamined all the main and sub-themes created during this approach to guarantee their utility and accurate representations of the data. The correctness of these themes was then reviewed. The writers then moved on to the next step by identifying the themes for each group and its subgroup. Prior to naming the themes for the sub-group, the authors began by naming the themes for the main group (see Table 1).

Theories	Numbers of studies	Method	Numbers of studies
Social exchange theory	11	Questionnaires and other empirical	31
Resource-based theory	9
Self-determination theory	4	Interviews	12
Full range leadership theory	4	Reviews	14
Great man theory	5	Mixed	23
Others/non-applicable	39
Leadership style	Numbers of studies	Themes	Numbers of studies
Transformational leadership style	20	Innovation performance	29
Transactional leadership style	14	Innovative work behavior	13
Laissez-faire leadership style	6	Innovativeness	17
Empowering leadership	8	Other innovation	20
Autocratic leadership	4	Sub-themes
Visionary leadership	4	Green innovation	6
Servant leadership	4	Sustainable innovation	8
Others	18

Table 1.

An analytical framework in literature.

3.2 Descriptive analysis

3.2.1 Regional distribution

This section evaluates the sample literature’s geographical distribution. The examination showed the studies were only in 23 nations, 22 were cross-country, and 12 were non-regional (Table 2). Due to insufficient national studies, we used Ascani et al.’s [36] continental classification [36]. China has the most articles in our sample, with five studies (6.5%). South Korea and Pakistan each had 4 studies (4%) on public and private firms integrating sustainable innovation via leadership [37].

Country	Numbers	Continent	Percentage
China	5	Asia	6.5%
South Korea	4	Asia	4%
Pakistan	4	Asia	4%
UK	4	Europe	4%
Taiwan	3	Asia	3.75%
South Africa	3	Africa	3.75%
New Zealand	2	Oceania	2.5%
Australia	2	Oceania	2.5%
Colombia	2	South America	2.5%
Norway	2	Europe	2.5%
Serbia	2	Europe	2.5%
USA	2	North America	2.5%
Laos	1	Asia	1.25%
Vietnam	1	Asia	1.25%
UAE	1	Asia	1.25%
Iraq	1	Asia	1.25%
Ghana	1	Africa	1.25%
Nigeria	1	Africa	1.25%
Indonesia	1	Asia	1.25%
Malaysia	1	Asia	1.25%
Lebanon	1	Asia	1.25%
Sri Lanka	1	Asia	1.25%
India	1	Asia	1.25%
Cross	22		27.5%
No country	12		15%

Table 2.

Regional distributions of studies.

Taiwan and South Africa were studied three times, whereas the remainder were studied fewer than twice. Some scholars conducted cross-country studies to evaluate economic and cultural disparities (22 studies). A study by Stremersch et al. [38] and Coun et al. [39] using samples from different nations found that transformational leadership boosts employee and organizational creativity. Studies can give researchers basic and crucial insights into a topic’s cultural, social, and political dimensions.

We also categorized the sample literature by its substance. Asia ranked first in the number of studies with 25 articles (e.g. [10, 40]), followed by Europe with 8 articles [41]. Despite its socioeconomic impact, only one US study exists. This suggests that the link between leadership and innovation in industrialized and emerging countries needs greater examination.

3.2.2 Leading research

Scopus’ citation matrix shows Table 3’s most influential research studies for leadership innovation link experts. Hoch and Dulebohn [50] has the most citations with 168. Leadership characteristics affecting innovation performance were studied. It also showed the relevance of leadership in helping organizations improve the team and organizational creativity and innovation. The study surveyed 184 Koreans. Another notable research with 79 citations is Kang J.H., [51]. This study studied the correlation between the founding CEO’s transformational/transactional leadership and the innovative behavior of managers. It was conducted in the USA using questionnaires from company managers. Frost D. [44] was cited 71 times. This study analyzed leadership and innovation in 15 nations. The study indicated that leadership styles influence subordinates’ innovative work and leadership support and decision-making.

Author/s and year	Citations	Country	Method/sample	Focus
[42]	168	South Korea	Questionaries 184	Shared leadership as a collective within-team leadership and inventive conduct, as well as shared leadership antecedents in terms of team composition and vertical transformative and empowering leadership
[43]	79	USA	Questionaries 105	The links between the original CEO's transformational/transactional leadership and manager innovation
[44]	71	Cross country; 15 countries	Mixed	Leadership and innovation
[45]	60	UK	Interviews 439	This study examined TL's impact on product and process innovation
[46]	44	USA	Mixed 158	This study examines transformational leadership, organizational innovation, and motor carrier performance
[47]	38	Colombia	Questionaries	Leadership, organizational learning, and organizational innovation in finance and IT
[48]	36	Pakistan	Questionaries 160	This research aims to determine the effect of leadership styles on innovative work behavior among Heads of Departments.
[49]	35	cross	Questionaries 339	This research proposes and tests a model linking individual views of participatory leadership style and managerial practices (i.e. teamwork and information sharing) to individual inventive behavior through team support for creativity, team vision, and psychological empowerment.
[10]	33	China	Questionaries 294	Transformational leadership builds trust and identity

Table 3.

Top 10 leading articles in the sample.

3.2.3 Research approaches used in the analyzed articles

The authors of 31 of the 80 papers included quantitative empirical research. The other studies were either theoretical or qualitative. Six publications used a case study technique, and five papers were conceptually oriented. A strategy known as cross-sectional data collection was used to gather information from a single source, the employees, in 19 papers out of 31 quantitative investigations. Multi-source data were only used in six research. In addition, the final sample only included three multilevel studies. The authors used secondary data in two research. There was 23 research that used a hybrid methodology. Thirty-seven papers employed partial least square structural equation modeling (PLS-SEM), and thirteen articles used regression analysis. Three research studies each used valuation ratios and SPSS Macro Process.

3.3 The analytical framework

3.3.1 Theories employed in the extracted articles

The inquiry comprised 80 studies, however only 42 depended on theories, which were allocated as follows. Socioeconomics 11 studies RBT 9, Self-determination 4 types of research leadership theory Great man theory: 4 studies 9 research in the literature employed mixed studies; details are below.

3.3.2 Social exchange theory

11 papers employed social exchange theory in this review, for example, the studies of [52], Jiang D. and Chen Z. [53], Li L. and Wang S. [54], Echebiri C.K. and Amundsen S. [55], and Liao S.-H. [56]. Homans proposed social exchange theory (1958), All human actions, including material and nonmaterial exchange, attempt to meet demands and attain pay and return equality, he said [57]. Blau [58] refined and developed the social exchange theory, noting that people interact socially to maintain favorable relationships, which promote reciprocity and social exchange behavior. Economic exchange is based on the exchange of interests, while social exchange is based on long-term mutually beneficial relationships and trust. The social exchange theory explains the relationship between paternalistic leadership, constructive deviance, and inventive conduct. Interaction with others influences an employee’s constructive deviance, and intimate ties between leaders and subordinates come from employees feeling inspired by leaders’ compassion and impartiality, producing a high-quality hierarchical exchange relationship. Sympathetic leaders boost employee engagement and exchange balance. This helps leaders and staff maintain long-term, beneficial connections.

3.3.3 Great man theory

This was based on the idea that particular people possessed certain traits [59]. It is believed leaders are born with intrinsic characteristics and intended to lead. Until the late twentieth century, leadership was seen as a male realm, especially in the military and Western penmanship [59]. Leadership was regarded as a complex phenomenon involving the leader’s psyche and personality. These theories likely stemmed from the era’s prominent leaders. In 9 research using the great man idea, most writers found that outstanding leaders are born with distinct abilities that shape the company [37, 60].

3.3.4 Self-determination theory

This theory has been successfully applied to parenting, education, healthcare, sports, physical activity, psychotherapy, virtual worlds, and job motivation and management [61, 62]. SDT demonstrates that job motivation affects employees’ performance and well-being. Various types of motivation have different catalyzers, concomitants, and repercussions, according to SDT. Only 4 studies based on self-determination theory were discovered in the study sample [38, 63].

3.3.5 Full-range leadership theory

In the study sample, 4 studies were based on full-range leadership theory. All the authors found that full-range leadership is an important theory, where leadership techniques use a situational strategy [64, 65]. One of the best-known no charismatic leadership ideas is the full range of leadership theories (FRLT; [66, 67, 68]). Transformational leadership is key to the theory. Leaders encourage followers by giving an enticing future vision, meeting their wants, or stimulating their inventiveness [69]. The theory’s leadership techniques are criticized, nevertheless. Several crucial leadership factors may still be missing from the FRLT, according to some [70, 71]. Offermann et al. [72] note that implicit leadership theories may reveal new leadership elements. This research identifies additional leadership factors. Examining followers’ and supervisors’ implicit leadership theories (ILT) reveals leadership traits and styles that correlate with leadership effects. The purpose was to expand leadership thought and add to FRLT.

3.3.6 Resource-based theory

In 1991, Jay B. Barney’s Journal of Management included a special research forum on the resource-based approach of the organization. The forum posts established that resources and capabilities are key for understanding business competitive advantage [73]. They helped define resources and capabilities as bundles of tangible and intangible assets, including a firm’s management skills, organizational procedures and routines, and the information and knowledge it controls to help determine and implement plans. In the framework of this theme, special forum papers focused on the RBV [73], resources and diversification [74], CEOs as resources [75], and organizational identity as a source of competitive advantage.

3.4 Leadership styles

3.4.1 Transformational leadership

In 20 research based on transformational leadership, we can state it’s an effective style for creativity and inventive subordinate work behavior. Transformational leaders change self-focused followers into enthusiastic ones. Transformational leadership encourages self-confidence, morale, and drive to attain a group goal [48, 56]. It’s a process-oriented theory that encourages followers to work toward a common goal and values their efforts. Transformational leaders gain followers’ respect, trust, and admiration [76, 77]. This strategy requires task and relationship support, which depends on resource availability and allocation [78]. Transformational leaders have unique behavioral traits. Transformational leaders create, express, and inspire a vision. Second, they help people grow their talents and challenge them to be top performers by providing training, resources, and the power to make decisions and innovate [79]. They model charismatic, influential leadership for their followers.

3.4.2 Transactional leadership

Transactional leadership focuses on the leader’s and followers’ individual interests by creating goals, assessing progress, and avoiding errors [56]. Transactional leadership helps adopt new company processes effectively [10]. It’s a conventional management style that addresses followers’ roles, obligations, and rewards. Transactional leadership impacts organizational learning under stable settings for reinforcing and refining knowledge [80]. It also requires monitoring followers’ performance to ensure company goals are accomplished or to conduct corrective actions [81]. Transactional leadership is less innovative than other kinds. Transactional leadership is the second most effective approach for innovation in an organization, according to 14 out of 80 research.

3.4.3 Laissez-faire leadership

Laissez-Faire is a hands-off, let-things-run leadership style. In this leadership style, employees are allowed to do as they like without intervention from bosses. Laissez-faire leaders are inactive and do not want feedback or to fulfill followers’ leadership needs [82]. Thus, distinguishing a leader from subordinates is difficult. Under this method, employees can conduct their duties as they see fit [83]. This style is based on six studies with varied innovation-related results.

3.4.4 Empowering leadership

In the sample, 8 research are based on empowering subordinates, especially in decision-making. EL is “power-sharing behavior” [20]. EL is a distinct and effective leadership style Vecchio et al. [20]. Empowering leaders allow subordinates to make independent decisions [84] to encourage followers to manage and regulate their own behavior [85]. EL is a form of socio-structural empowerment [86] and employee empowerment [77, 87]. The EL style aims to improve individual motivation at work by delegating responsibility and authority to the lowest organizational level [87, 88]. An empowered leader encourages initiative, self-reliance, positive thinking, and problem-solving [85]. EL helps employees acquire self-control and behave independently [20], develops followers’ self-leadership skills, and encourages opportunistic thinking [3]. Lee et al. [86] compared empowering versus disempowering leaders in a meta-analysis. Employees led by an empowered leader are more likely to come up with innovative ideas and methods. EL is more successful for work goals requiring employee inventiveness and proactivity.

3.4.5 Autocratic leadership

This leader makes all decisions and policies alone. A dictatorship is characterized by force, intimidation, and authority in decision-making. Autocratic leaders set policies and allocate tasks without consulting followers. The reward-and-punishment mechanism underlies autocratic leadership. Autocratic workers follow orders without question [89, 90]. Autocratic leadership has been studied four times. Most results were unfavorable for innovation.

3.4.6 Servant leadership

Four servant leadership studies are in the sample. In servant leadership, the leader empowers and involves subordinates in managerial choices. They help followers enhance their skills and act ethically and with strong principles. Servant leaders prioritize followers’ needs. They focus on all organizational stakeholders and engage the community. Trust is the key trait of servant leadership and is related to followers’ trust in leaders and organizations and leaders’ empathy and competence. This leader-follower relationship makes employees feel emotionally safe about their leadership’s goals, increasing their dedication and readiness to innovate, produce new ideas, and start change. Therefore, there is a positive relationship between employees’ perception of servant leadership and their innovation implementation behavior, which can be strengthened by the empowerment role identity, which makes an employee more comfortable making work-related decisions, having more role autonomy, and taking on new challenges. Creative role identity can increase the interaction between servant leadership and employees’ innovation implementation by providing the support needed to adopt new ideas in a benevolent atmosphere [91].

4. Thematic analysis

Concepts within themes were chosen to identify the key themes and ideas that emerged from the systematic review of the studies. In these investigations, which present concepts as spots and themes, concepts that regularly travel together come up together intensely and are exhibited close together. The most used notion within each theme serves as the basis for the names of the themes in the final concept. The most significant topics that emerged from our analysis of the links between leadership and innovation include innovation, innovation performance, innovative work behavior, and innovativeness, as shown in Table 1. Table 1 also includes illustrations of the primary themes and their hits. The main themes, apart from the themes of potential, industry, and analysis, involve other ideas and are related to one another in various ways. The analysis reveals that one of the primary themes examined in 29 studies, particularly transformational leadership, and transactional leadership, has a substantial relationship with innovation performance. While the relationship between leadership and innovation was studied in 17 papers. The investigation discovered 13 studies that looked at the relationship between innovative work behavior and leadership. The words “leadership,” “green innovation,” “relationship,” “sustainable,” and “employees” also appear as concepts, indicating a strong relationship between leadership practices and employee green innovation and sustainable innovation, even though the sub-theme of “green innovation and sustainable innovation” includes the adjective “strong.” Green appears to serve as a connecting factor between organizational change and environmental innovation, which promotes the growth of sustainable innovation. The idea of sustainability also supports a strong and direct relationship between leadership and innovation. Although the concepts of leadership and green innovation and the concept of performance do not directly relate to one another, it is obvious that leadership can have a substantial impact on innovation performance through the chain reaction of these concepts.

On the other hand, the theme of sustainable innovation and the ideas of study, impact, and data are related to leadership, and these connections help to interpret the function of innovation in the business process. It is also obvious that research on the possible effects of innovation will probably give practitioners useful information. It has been demonstrated that businesses can alter their behaviors by adopting green standards, which helps to attain sustainable innovation performance, and that sustainable innovation has an indirect relationship with leadership via change. The intersection of leadership and green innovation is supported by a link between sustainability, innovation, and green themes, according to the thematic analysis. As may be predicted, research on leadership, innovation, and sustainability predominates, but studies on green innovation have yet to garner the attention they merit. Therefore, to increase understanding of green adaptive behaviors in companies, future studies should concentrate on green creativity and its antecedents in the service sectors. The analysis found that prior research covered a wide range of topics related to innovation through leadership. These themes were further developed in our review with the goal of methodically filling this knowledge gap. These studies concentrated on the ways in which leadership affects innovation. Leadership philosophies and innovation performance were examined by Gallego-Nicholls et al. [92] and Al-Diery et al. [93]. The effectiveness of innovation was positively impacted by transformational, transactional, laissez-faire, empowering, servant, and visionary leadership styles (innovation, innovativeness, innovative work behavior, sustainable innovation, and green innovation). Leadership philosophies and innovation performance were examined in 27 studies. Innovation and leadership were associated in 13 studies. 11 studies show a connection between innovative workplace behavior and leadership styles. The results demonstrate that both transactional and transformative leadership are useful for innovation. According to studies, other leadership philosophies such as laissez-faire, servile, and autocratic are ineffective.

4.1 Implementing an effective leadership style

According to Reyes-Guerra et al. [94], effective leadership is dependent on the qualities and abilities of the leader, which are manifested in leadership behavior. A healthy work environment is correlated with leadership behaviors including transformational leadership, transactional leadership, servant leadership, authentic leadership, distributed leadership, and instructional leadership [95, 96]. The transformational leadership style is the most researched and effectively tested of the various leadership philosophies used today. Due to its nature, which is driven by a leader’s capacity to leverage organizational members to realize their goals and vision, transformational leadership has been identified via numerous studies as the most effective leadership style in a variety of companies [97, 98]. Researchers have repeatedly discovered that leadership has a significant impact on how employees act innovatively, which has increased interest in the study of safety leadership. Wu [99] pointed to the innovative leadership of university top leadership as the relationship between leaders and followers in which a leader can exert influence on followers to achieve organizational goals within the framework of individual and organizational components. This leadership style has a favorable effect on the performance of the organization’s innovation [6, 48].

5. Discussion

This report shows the large picture of leadership and innovation research in connection to and identifies directions for future research through a survey of 80 publications published between 2012 and the first half of 2022. It demonstrates that leadership is regarded as a key factor influencing green innovation and sustainable innovation (e.g., [100, 101, 102]) and that research in this area is expanding, with all the studies, we included in our study having been published within the past ten years. Our review also reveals that interest in innovation research is increasing, which is consistent with earlier research such as [103]. For instance, many academics have abandoned the idea of generic innovation. The huge rise in studies that began in 2018 reflects the progress that has been made in using a sustainable innovation study paradigm and offers remarkable actionable advice. An academic understanding of green innovation and sustainable innovation is necessary despite the recent emphasis on environmentally friendly methods by many academics.

The results show that Western nations have greater leadership, inventiveness, and green innovation than their developing counterparts. This suggests that academics from Asia are becoming more concerned with innovative work behavior and are concentrating more on reducing the negative effects of innovation performance. The results demonstrate that qualitative research predominates over other methods of research (i.e., qualitative, mixed method, and conceptual). Most quantitative analyses have traditionally employed surveys as a method of gathering data. To uncover and clarify novel concepts and phenomena, however, there appears to be an urgent need for qualitative, conceptual, or at least mixed-method research given the nascency of this topic. To theoretically support the indicated links (such as leadership-green-innovation, sustainability, and innovativeness) and influence the future of the study domain, academics should concentrate on providing concepts, theories, and techniques [104]. Future efforts can focus on creating customized measures for the study domain to better capture the dyadic interaction. To investigate the potential implications of leadership styles, scholars have chosen a variety of theories. For instance, the resource-based view has been used as the theoretical basis for responsible leadership studies to examine green transformational leadership [105], while the resource-based view has also been used to examine environmental leadership [106], and social exchange theory [102]. (e.g., [47]). Studies analyzing the connection between innovation and servant leadership have also referenced the conservation of resources hypothesis (e.g., [107]). These findings demonstrate the absence of a widely acknowledged theoretical framework that can support the link between leadership and green innovation. Future studies in the field of service research will be greatly influenced by this theoretical gap. Based on the primary conclusions of our study, we offer specific recommendations for further research in the fundamental areas below. We also provide potential research topics based on the three domains, which can encourage academics to carry out additional research in the field of service research.

5.1 Future research agenda

5.1.1 Research methods

Even though all the studies in our sample were interested in causal effects, the majority of them were unsuitable for this goal due to poor study design and/or endogeneity problems. As a result, we offer the following methodological advice to guarantee that future studies carefully address causal issues.

First, longitudinal studies with adequate time lags should be preferred in the future to cross-sectional study approaches. According to the review’s conclusions, case studies will be helpful because they will make it simpler to explain and enhance innovation performance in this relatively new subject. This is because case-study methodologies allow researchers to incorporate the opinions of industry practitioners and other experts. The bulk of earlier studies (38.7%) relied on survey techniques, which have constraints that make it unlikely that the findings will add to our conceptual knowledge of the service environment., there aren’t many qualitative research techniques in the literature yet. Careful qualitative research can assist establish solid theoretical underpinnings for a research area in its infancy, leading to the creation of precise constructs that are appropriate for the field’s unique qualities. Therefore, we support additional studies in this area. However, when it comes to research methodology, we support multilevel studies that look at leadership as a concept at the group or organizational level. Because leaders typically engage in behaviors that are addressed to individual employees rather than a group, and because followers working in the same department and/or organization tend to be more influenced by group-level or firm-level leadership, such research could advance knowledge of leadership in employee innovation practices, including employee green innovation and sustainable innovation [108, 109].

5.1.2 Measurement scales

This study discovered that lower-order determinants of innovation performance were not adequately addressed in the literature. For instance, the innovation scale initially created by Chen et al. [110] comprises four elements for each of the subdimensions of product innovation and process innovation. However, researchers looking into the connection between leadership and innovation have not made a distinction between these parts and have viewed the measurement of sustainable innovation as a single element. As a result, researchers who intended to study innovativeness unintentionally evaluated product innovation, and vice versa. In this regard, the ramifications of our findings are rather obvious. Deeper tools are a must for a better knowledge of innovation and sustainable innovation performance, and future research must focus on the person, the process, and the product. The development of metrics to gauge the promotion of green ideas, evaluation of the effectiveness of green idea promotion, and assessment of how teams or individuals originate and implement green ideas are some possible future stages. With these new initiatives in place, it will be feasible to define the roots of sustainable development and green innovation, including in terms of leadership behavior.

5.1.3 Leadership styles

According to our review, effective leadership practices are strongly correlated with innovation and long-term innovation performance. Most of the study, however, has only looked at the effects of transformational leadership and transactional leadership on creativity, inventiveness, and innovative work behavior. As a result, attention is seldom given to how bad leadership practices can hinder innovation. Furthermore, it is uncertain which leadership philosophies are the best predictors of creativity and innovativeness due to the lack of analysis of the contributions of various leadership characteristics. Investigating the leadership traits that most effectively forecast green and sustainable innovation is thus necessary. For this, a focus on leadership styles will not be sufficient, thus future research must examine the effect of leaders’ identities (including their personality, knowledge, and behaviors). Even if we only concentrate on leadership styles, our analysis reveals that the bulk of studies has concentrated on measuring leadership styles as a single construct (ignoring the different dimensions of the transformational, transactional, servant, and authentic leadership). The performance of green innovation and sustainable innovation should be examined in relation to the sub-components of leadership styles, as well as the dimensional effects of various styles, in order to overcome this deficiency.

However, we discovered that various academics have looked at well-known general leadership techniques and styles that can accurately predict both green innovation and sustainable innovation [111, 112]. However, there is a chance for scholars to assist the growth of theory and interdisciplinary study in the business management literature given the growing interest in leadership and green practices, such as innovation and sustainability. Researchers could start by creating a green-specific leadership strategy that supports the overall advancement of the sustainable business management field as a research discipline and moves it beyond its current reliance on theoretical frameworks from other fields, such as information sciences, behavioral sciences, psychology, and finance. Since an organization can be described by its leader, this would be a good place to start. Researchers might, for instance, create a new theory of green leadership that emphasizes ecologically responsible leadership practices in a company with an emphasis on defining the identity and traits of such a leader (in terms of, for example, personality and intelligence). Like, this leadership style might be explained in terms of the knowledge a green leader needs to have to run an organization effectively and efficiently. Finally, researchers could define the behaviors expected of green leaders, such as the specific management implications of their activities and how they support sustainable innovation. Future researchers are urged to quickly create this new theoretical approach considering the probable requirement for leadership.

The lack of clarity, particularly in terms of theory and causality, poses a threat to working based on multidimensional definitions of leadership, so future attempts to develop appropriate scales that concentrate on the lower-order constructs of transformational leadership should take this into consideration. Ways to emphasize the connection between leadership styles and innovation (Table 4).

Authors and year	Country/LS/method/sample	Focus	Findings
[92]	Korea transformational/transactional Questionnaire (414)	Innovation performance through leadership styles	Both leadership approaches boost organizational creativity. Leadership via check and balance can boost innovation performance
[113]	Cross countries mixed	Leadership styles and firms’ innovation	Transformational and transactional leadership styles predict absorptive capacity and inventiveness
[114]	Taiwan interviews 100	Leadership and innovation	Leadership is the most important predictor of subordinates' creativity and innovation, research shows
[115]	Cross countries Empowering leadership Questionaries 257	Empowering leadership and innovative work behavior	Findings highlight the relevance of empowerment in sustaining innovative work-behavior, especially in intense and lasting remote work situations, as this can magnify employees' ability, incentive, and chance to produce, communicate, and apply unique ideas. In distant work situations, empowered leadership can stimulate creativity indirectly through work-related flflow, which has become more essential over time. Directive leadership reduces workflow and hinders creativity
[116]	Cross countries Mixed; 64	Leadership and organizational innovation	Results show that transformational and transactional leadership styles can boost employee innovation. The study found a link between transformational and transactional leadership and innovative behavior. Innovative behavior is influenced by leadership, inspiration, intellectual stimulation, and contingent reward. Individual consideration, management-by-exception, and innovative behavior revealed no link
[117]	South Africa Questionnaire 3180	Leadership and innovative work behavior	The results show that transformational and transactional leadership styles can boost employees' inventive behavior. The study confirmed a link between transformational and transactional leadership and innovative behavior. Leadership styles, motivation, intellectual stimulation, and contingent reward promote innovative behavior. Results demonstrated no link between individual consideration, management- by-exception, and innovative behavior

Table 4.

Sample of the studies on leadership styles and innovation.

6. Conclusions and recommendations

Sustainable innovation is gaining popularity in business, society, and academia. Few empirical and review research explore leadership’s role in innovation performance. This study included 80 studies from a systematic literature review to examine the role of leadership in innovation. The study found that having a leader improves an organization’s reputation, planning, structure, monitoring, and innovation performance. This paper reviews the available literature on effective leadership to enhance innovation. It shows the role of leaders in promoting practical innovation to the extent desired by stakeholders and confirms innovation’s importance to organizational success. The results demonstrated that leadership is vital, especially when the market and environmental pressures are involved. The findings may help regulators and practitioners comprehend the leadership and innovation link of the le field and allow for new and exceptional empirical studies. Current innovation procedures must be altered to improve the professionalism of this technology through training and funding. Due to different aspects/research subjects of sustainability assurance, auditors should define the criteria employed and refer to established standards to strengthen the credibility of their verification and the readability of subordinates toward new idea generation. Subordinates should be involved in revising innovation to improve its quality and standard. This study has limitations, like others. We used keywords to discover sample material in Scopus, a peer-reviewed abstract indexing database. Future studies may use the Web of Science, ABS, and ABDC. The search method utilized in this study was limited, thus the findings may not include all relevant documents. Future research could add sustainable development or disclosure to the search query.

The current study had limitations despite its contributions. First, while our cross-sectional research approach sheds insight into the linkages between our study’s main variables and changes, we did not analyze causal relationships across time. Wipulanusat et al. [118] study solely Anglo-Saxon Australia. This restricts the generalizability of findings across cultures. Future studies should focus on cross-cultural features and mixed methodological.