Safety-specific transformational leadership and safety outcomes at workplaces: a scoping review study

Abstract

Background and aim

Safety-specific transformational leadership (SSTL) has garnered much attention in recent years. This scoping review aims to explore; (1) the industries within which the impacts of SSTL are investigated; (2) the impacts of SSTL on the leading and lagging safety indicators; (3) mechanisms through which SSTL can affect safety outcomes; (4) the safety impacts of SSTL compared with other leadership styles; and (5) research gap to be covered by future studies.

Materials and methods

This review was conducted in accordance with the standard procedure proposed by PRISMA-ScR. Three major databases including Web of Science, PubMed, and SCOPUS were searched. After removing duplications, initial screening, and eligibility assessment steps, 28 articles were included in the study.

Results

Coined in 2002, SSTL is a distinct construct from general transformational leadership with a greater influence on safety outcomes. Most studies are conducted in Canada and among construction workers. SSTL could affect both leading and lagging safety indicators, particularly safety behavior and occupational accidents. Safety climate and safety motivation mediate the impact of SSTL on safety outcomes. Social exchange theory and leader-member exchange theory explain how SSTL can modify the safety behavior of employees. SSTL is much stronger than passive leadership in affecting safety, and its effects are comparable with safety-specific active transactional leadership.

Conclusion

SSTL appears to be a significant factor influencing workplace safety outcomes, affecting both leading and lagging safety indicators. However, long-term longitudinal studies are needed to fully understand the impact of SSTL on these safety outcomes. Additionally, safety knowledge could serve as a mediator in the relationship between SSTL and safety results. Future research should compare the effectiveness of SSTL with authentic leadership style in enhancing safety outcomes. It would also be beneficial to assess how well SSTL can mitigate the negative effects of factors such as occupational fatigue, work-family imbalance, and production pressure on workplace safety.

Introduction

Occupational accidents result in a significant number of fatalities each year, making it crucial for companies to manage them effectively [1, 2]. Research has shown that various situational, organizational, and personal factors influence industrial accidents. One important organizational factor is leadership, which plays a major role in accident prevention. Leadership can be defined as the process of influencing others to achieve specific goals, and effective leaders excel at this [3]. Strong leadership has the power to transform struggling organizations into highly profitable ones [4, 5]. As a dynamic and complex characteristic [6], leadership is a vital aspect of management that greatly impacts several areas within organizations, including job performance, productivity, job satisfaction, and psychological well-being [7–9]. Furthermore, leadership has been identified as a key factor in determining safety outcomes, such as safety climate and safety performance [10, 11]. It is also crucial for the effectiveness of management systems, including ISO (International Organization for Standardization) standards related to occupational health and safety (OH&S) management systems (e.g., ISO 45001).

Leadership styles have evolved in response to changes in people, societies, and working environments [12, 13]. Some styles, such as laissez-faire and passive-avoidant, are notorious for their lack of engagement and their negative impacts on organizational performance, as well as on employees’ health, well-being, and job satisfaction [13–15]. The transactional leadership style, which emphasizes rewards and punishments to motivate employees, has also faced criticism [13, 16]. This approach relies on external motivations and overlooks the beliefs, values, and attitudes of employees [17].

Servant, resonant, authentic, and transformational styles are more active than former ones, attempting to influence and empower the subordinates using different approaches. Servant leaders intend to empower followers and assist them in achieving their objectives [18]. Resonant leadership is based on the sharing of emotions between the leader and followers, creating a positive work environment to boost safety outcomes [19, 20]. Authentic leaders prefer to develop professional close relationships with followers based on honesty and transparency. Information sharing in an open, positive, and comfortable environment, increasing the awareness of both leaders and followers, considering positive psychological capital and moral aspects, enhancing positive organizational context, and valuing the viewpoints of subordinates are characteristics of this leadership style [21–23].

Transformational leadership aims to enhance employees’ attitudes and beliefs, fostering greater loyalty to the organization and motivating them to strive for organizational goals beyond expectations [24]. This leadership style is one of the most widely studied and recognized across the globe [13, 25]. Compared to other leadership approaches, transformational leaders are often more successful at influencing their followers [24, 26–28]. The concept of transformational leadership was first introduced by Burns in 1978 [29] and later developed by Bass [30]. Unlike transactional leadership, which focuses on rewards and incentives, transformational leadership seeks to create positive changes in followers’ attitudes, beliefs, and values, encouraging them to work towards set goals and objectives [31]. The main components of transformational leadership include idealized influence, inspirational motivation, individualized consideration, and intellectual stimulation. Charisma plays a significant role in the effectiveness of transformational leaders, highlighting their ability to impact followers through their personal characteristics [31]. These leaders encourage their followers to prioritize organizational goals over personal ambitions, aiming to meet employees’ higher-order needs rather than just their basic physiological needs [32]. This style can also foster a positive patient safety culture in healthcare settings [33] and promote a favorable safety climate in workplaces [34].

Safety-specific transformational leadership style (SSTL), first introduced by Barling et al. [35], is a subcategory of transformational leadership that specifically addresses safety-related issues. Barling et al. [35] defined five main components for SSTL, including four original components from transformational leadership (i.e., idealized influence, inspirational motivation, intellectual stimulation, and individualized consideration) and contingent reward. All these components influence safety and occupational injuries in different ways. Idealized influence means managers are fully committed to safety and demonstrate this commitment using every available opportunity, such as actively participating in safety-related activities and maintaining a safe workplace. Inspirational motivation means managers establish an entrancing safety vision for the employees. They instill in employees the belief that accidents are preventable and that jobs should be carried out without accidents or injuries. Intellectual stimulation means leaders encourage employees to be innovative and creative in developing novel ways to improve safety in the workplace. Individual consideration means managers value the health, safety, and well-being of their subordinates, address their safety concerns, and show them safe work practices. Contingent reward means managers appreciate and reward the good safety performance of their employees [35–37].

SSTL focuses on the long-term improvement of safety by boosting the beliefs, values, and attitudes of employees toward safety [38]. It differs from practices based on transactional leadership or safety-specific transactional leadership in that incentives and rewards are crucial tools to improve safety performance [5]. In contrast to passive leadership styles, SSTL, as an active form of leadership, can remarkedly improve safety climate perceptions, safety behavior outcomes, and employees’ safety motivation at workplaces [11, 39, 40].

Since the introduction of SSTL, a high volume of studies has explored its impacts on various leading and lagging safety indicators, including safety performance, safety climate, safety behavior, and occupational accidents. These studies have been conducted across different sectors and have tested diverse hypothetical models, resulting in some contradictory findings. While several literature reviews have examined the influence of safety leadership on safety outcomes, none have specifically concentrated on SSTL. For instance, Clarke’s meta-analytic review in 2013 [41] concentrated on all types of safety leadership styles and considered safety behavior as the sole safety outcome, the review by Jiang et al. [42] focused on the bibliographic information of various safety leadership styles, while Adra et al. [43] provided an overview of the different definitions of safety leadership. Therefore, a new review specifically addressing SSTL and its impact on a range of safety outcomes—such as safety performance, safety behavior, and occupational accidents/injuries—is necessary. This study aims to conduct a scoping review on SSTL and its effects on safety outcomes. We have chosen the scoping review methodology because it tackles broad questions within the subject area and offers a comprehensive overview of existing studies in this particular field. By not including certain analyses such as risk-of-bias assessment or meta-analysis, commonly found in systematic reviews, we minimize the chance of overlooking relevant publications [44]. This study will be valuable not only for occupational health and safety engineers but also for individuals in managerial and supervisory roles. The questions this scoping review seeks to answer include: (1) What are the bibliographic characteristics of the studies conducted on the subject of SSTL? (2) In which industries are the impacts of SSTL investigated? (3) What are the impacts of SSTL on leading and lagging safety indicators? (4) What mechanisms enable SSTL to affect safety outcomes? (5) How does the impact of SSTL on safety indicators compare with other leadership styles? (6) What research gaps remain for future studies to address?

Materials and methods

This scoping review study was conducted following the PRISMA Extension for Scoping Reviews (PRISMA-ScR) guidelines [44]. While a scoping review shares many similarities with a systematic review, it deals with broader research questions [44]. Figure 1 illustrates the main steps involved in this study.

Fig. 1.

The main steps of the present study

Initial search and finding all relevant studies

In this study, we examine three primary databases and search engines: SCOPUS, Web of Science, and PubMed, to identify relevant high-quality articles. SCOPUS is one of the largest abstract and citation databases; PubMed is a free search engine that allows users to explore documents in the fields of biomedical, health sciences, and life sciences from the MEDLINE database; and Web of Science is a platform dedicated to high-quality journals. Our approach aligns with that of previous studies on similar topics [45]. We included all publications that contain the term “safety-specific transformational leadership” in their title, abstract, or keywords, published before May 31, 2025. Following this, we reviewed the records and removed any duplicates. It is important to note that “records” refer to all items and documents retrieved from the database searches, which may include books, book chapters, newspapers, bulletins, and other types of publications.

The focus of this scoping review was on the original studies investigating the effect of SSTL on safety outcomes. Consequently, we excluded review articles, books, book chapters, book reviews, bulletins, newsletters, and all other kinds of non-original records. Moreover, we also excluded original studies regarding SSTL as the dependent variable or investigating the impact of SSTL on non-safety-related outcomes.

Singling out relevant studies

To identify relevant studies, two independent researchers, F.G. and M.M., screened the titles and abstracts of all remaining papers. If there was any disagreement between the researchers, the record was forwarded for further consideration. Subsequently, the full texts of all selected papers were thoroughly examined. During this stage, non-original records, studies where SSTL was the dependent variable, and studies investigating the impact of SSTL on non-safety-related outcomes were excluded. F.G. and M.M. conducted this step, resolving any disagreements through discussion.

Extracting the required data

In this step, we extracted the required data from the included articles based on the study’s objectives. The extracted data comprised the year of publication, the journal, the country and geographical region where the study was conducted, the occupations and industries involved, the theories used to interpret the findings, the tools used to measure SSTL, the data analysis techniques employed, and the effects of SSTL on safety outcomes.

Results and discussion

This section is organized in two main parts. In the first part, initial search results, screening, and eligibility assessment are presented. In the second part, we addressed research questions one by one.

Initial search, screening, and eligibility assessment

During our initial search, we identified 51 records in SCOPUS, 43 records in Web of Science, and 16 records in PubMed. After removing duplicates, 52 records remained for further analysis. F.G. and M.M. conducted an initial screening by carefully examining the titles and abstracts of these records. This process resulted in the exclusion of eight records: five were review articles (none related to SSTL), one was a book chapter, one was a non-original article, and one article was excluded due to the unavailability of the full text. The authors attempted to contact the authors of the unavailable article via email and other means but did not receive a response, leading to its exclusion. During this stage, the researchers disagreed on one record, which was investigated further in the next step.

In the eligibility assessment phase, the two researchers closely examined the full texts of 44 records. One record, being in a non-English language, was removed from the study. Additionally, eight records were excluded due to their irrelevance to the subject matter; these studies either did not investigate the impact of SSTL on safety-related outcomes or considered SSTL as the dependent variable. One study was also eliminated because it was not an original research article. Consequently, 34 relevant original articles were deemed suitable for inclusion in the final step of the study, which involved data extraction. Depicted in Fig. 2 is the PRISMA diagram of this study.

Fig. 2.

The PRISMA flowchart of this scoping review

The bibliographic characteristics of the studies

Table 1 provides a summary of the studies included in this analysis. All the studies were published after 2002, which is not surprising since this leadership style was first proposed in that year [35]. In terms of the geographical distribution of the studies, China leads with nine articles, followed closely by Canada with seven articles and the United States with six. Other countries represented include the United Kingdom with four articles, and Pakistan, Italy, and the Netherlands, each with two articles. Additionally, Malaysia, Hungary, and India each contributed one article.

Table 1.

A summary of articles included in this scoping review

Article	Country	Year	Industry/Organization	Participants	Sample Size	Dependent Variables
Lacerenza et al. [48]	The United States	2025	Construction	Leaders and employees	1062	Safety Compliance
Pasparakis et al. [49]	India	2025	Hazardous material transportation	Drivers	71	Safety Behavior
Yang et al. [50]	China	2024	Airline	Maintenance technicians	593	Work Engagement, Safety Behavior
Usman et al. [51]	Pakistan	2024	Healthcare	Nurses and physicians	384	Organizational Citizenship Behavior,
Wang et al. [52]	China	2023	Oil and Gas	Employees	527	Safety compliance, Safety Participation
Wu et al. [40]	China	2023	Airline	Pilots	332	Safety Behavior
Mo et al. [53]	China	2023	Construction	Employees	287	Safety compliance, Safety Participation
Nguyen et al. [54]	United Kingdom	2023	Construction	Employees	Study 1: 148 study2:412	Safety Compliance, Safety Participation
Shi and Zainal [55]	China	2022	Oil and Gas	Employees	255	Mindful Safety Practices
Cheung et al. [56]	The United States	2022	Construction	Employees	280	Safety Climate
Shi [57]	China	2022	Oil and Gas	First-line workers	306	Mindful Safety Practices
Xia et al. [58]	China	2021	Construction	Workers	120	Safety compliance, Safety Participation
Rafique et al. [59]	Pakistan	2021	Construction	Employees and Managers	294	Safety Attitude, Safety Behavior
Shi [60]	China	2021	Oil and Gas	First-line workers	255	Mindful Safety Practices
Smith et al. [61]	The United States	2020	Fire services	Firefighters	742	PPE Use Behavior
Mirza and Isha [62]	Malaysia	2020	Oil and Gas	Production Workers	270	Safety Climate Occupational Accidents
Cheung and Zhang [63]	The United States	2020	Construction	Construction Professionals	284	Safety Climate
McPhee et al. [64]	Canada	2019	Multiple industries	University students	376	Safety Behavior, Injury
Lu et al. [65]	China	2019	Construction	Workers	370	Near-miss Recognition
DeArmond et al. [66]	The United States	2018	Municipal Utilities	Municipal utilities Workers	314	Safety Goal Commitment, Safety Compliance, Safety Participation, Safety Citizenship Behavior
Mullen et al. [67]	Canada	2017	Multiple industries	1- Trade Apprentices. 2- Trade Employees	1: 115 2: 140	Safety Compliance, Safety Participation
de Vries et al. [68]	Netherlands	2016	Warehouses	Warehouse Managers and Employees	1233	Accident
Curcuruto et al. [69]	Italy	2016	Multiple industries	Employees	1:327 2:196	Safety Voice, Safety Initiative Risk Behaviors
Smith et al. [39]	The United States	2016	Fire Services	Professional Firefighters	349	Safety Climate Safety Compliance, Safety Participation
Toderi et al. [70]	Italy	2016	Construction	Workers	216	Safety Climate, Safety Compliance, Safety Participation
Conchie et al. [71]	United Kingdom	2013	Oil and Gas	Supervisor and Employee	150	Safety Voice-Citizenship Behavior
Conchie [72]	United Kingdom	2013	Construction	Frontline Employees	Stydy1: 251 Stydy2: 220	Whistle-Blowing Behaviors, Safety Voice Safety Compliance
de Koster et al. [36]	Netherlands	2011	Warehouses	Warehouse Managers and Employees	1111	Safety Consciousness, Accident
Mullen et al. [73]	Canada	2011	Healthcare	Healthcare worker	Stydy1: 241 Stydy2: 497	Safety Compliance, Safety Participation
Mullen and Kelloway [46]	Canada	2009	Healthcare	Leader and worker	Pre-training:54 Post-training:115	Safety climate, safety compliance, safety participation, safety-related events, Injuries
Conchie and Donald [74]	United Kingdom	2009	Construction	1: Supervisors 2: Frontline Workers	1: 33 2:139	Safety Citizenship Behaviors
Kelloway et al. [75]	Canada	2006	Multiple industries	Undergraduate Students	158	Safety Climate, Safety Consciousness, Safety-Related Events, Injuries
Sivanathan et al. [47]	Canada	2005	Aquatic centers	1: Swim Instructors 2: Swim Supervisors	1: 36 2: 21	Safety Compliance, Safety Participation
Barling et al. [35]	Canada	2002	Food and Beverage	Restaurant Workers	study 1: 174 study 2: 164	Safety Climate, Safety Consciousness, Safety Related Events, Injuries

Regarding the study designs employed, most studies were conducted using a cross-sectional approach. Specifically, 17.6% of the studies (six in total) were carried out using a two-time-lagged design, while only two studies were interventional: Mullen & Kelloway [46] and Sivanathan et al. [47]. This highlights the need for more interventional studies in this field.

As shown in Fig. 3, the 10-item scale developed by Barling et al. [35] is the most widely used tool for measuring SSTL, having been employed in 22 studies (64.7%). This scale is based on MLQ created by Bass and Avolio [76]. It measures the four subscales of transformational leadership, with two items dedicated to each subscale, along with two additional items for the contingent reward aspect. Exploratory and confirmatory factor analyses confirmed that a single-factor model underlies this scale [35]. In 2009, Conchie and Donald [74] improved the construct validity of the scale by removing two items related to the contingent reward subscale. Five studies utilized this revised 8-item scale. Four studies mentioned employing the 10-item scale developed by Kelloway et al. [75] in 2006. This scale is quite similar to Barling et al.‘s [35], with both featuring ten items, being rooted in the MLQ, and measuring each MLQ subscale with two items.

Fig. 3.

Tools used to evaluate SSTL

Additionally, Toderi et al. [70] translated and validated the scale into Italian. One study by Lacerenza et al. [48] applied a shortened 4-item version of Barling et al.‘s 10-item scale, using one item to measure each of the four subscales of SSTL. Another study, by DeArmond et al. [66], developed a 7-item SSTL scale based on the Global Transformational Leadership (GTL) scale from Carless et al. [77]. According to Carless et al. [77], the GTL is strongly correlated with the MLQ. Since the MLQ serves as the foundation for most scales used to assess SSTL, it can be concluded that the underlying definition of SSTL remains consistent across the various studies.

The distribution of articles across industries

Figure 4 illustrates the various industrial and service sectors where the included studies have been conducted. The majority of the research, accounting for 32.4% (11 cases), has taken place in the construction industry, followed by the oil and gas sector, which represents 17.6% (six cases). Other areas investigated include fire services, healthcare, warehouses, food and beverage manufacturing, hazardous material transportation, aquatic centers, and municipal utilities. Notably, four studies (11.8% of the total cases) were conducted across multiple industries. These findings align with the observation that the risk of occupational accidents is particularly high in environments such as construction sites, oil and gas facilities, and healthcare centers [78–80].

Fig. 4.

Industrial and services domains in which the articles are conducted

The relationship of SSTL with leading and lagging safety outcomes

To date, the relationship between SSTL and a variety of safety indicators and outcomes has been investigated. Figure 5 summarizes the various dependent variables associated with SSTL. Research has focused on both leading and lagging indicators. Among these, safety compliance (17 cases), safety participation (16 cases), and safety climate (9 cases) have been studied most frequently. These indicators are among the most significant leading indicators of safety and key determinants of accidents [81].

Fig. 5.

The safety outcomes upon which the effect of SSTL is investigated

Safety compliance refers to the extent to which employees follow safety standards, rules, regulations, and standard operating procedures. In contrast, safety participation entails voluntary activities that promote safety within the workplace [82]. While both constructs are integral to safety performance, they represent fundamentally different behaviors. Safety compliance is a mandatory behavior essential for preventing accidents and occupational injuries, whereas safety participation is voluntary and reflects an employee’s commitment to enhancing workplace safety [52, 82, 83]. In many organizations, failure to comply with safety regulations may lead to disciplinary actions, while participation in safety initiatives can often result in rewards. Safety climate, on the other hand, is the shared perception among employees regarding the importance of safety within the organization, as well as among upper management [84].

Many studies investigating safety outcomes focus on various forms of safety behavior. These include risky behavior, the use of personal protective equipment (PPE), mindful safety practices, commitment to safety goals, safety consciousness, and even safety citizenship behavior. Additionally, many of the variables discussed fall under the category of occupational incidents, which encompasses injuries and safety-related events. As a result, most research concentrates on safety behavior, while a smaller portion addresses occupational incidents. The findings from the reviewed studies consistently indicate that SSTL has a significant impact on safety outcomes, particularly safety behavior and occupational incidents.

Studies repeatedly applied correlation coefficients to express the relationship between SSTL and other variables. Table 2 showcases the results of this section. Except for three cases, Nguyen et al. [54], Conchie et al. [71], and Lacerenza et al. [48], the correlation between SSTL and safety outcomes was reported to be significant in all other studies. In this regard, Lacerenza et al. [48] and Nguyen et al. [54] did not find a significant correlation between SSTL and safety compliance, and Conchie et al. [71] did not report a significant correlation between SSTL and safety voice. As SSTL is about inspiration and motivation, it is more associated with safety participation than safety compliance, because safety participation needs a high level of commitment and motivation [85]. This explanation is in line with studies reporting a significant correlation between motivation and safety participation [86, 87].

Table 2.

The number of articles reporting a significant and non-significant correlation between SSTL and other safety outputs

SSTL and…	Significant	Non-Significant	Relationship Type	The significance level (p-value)
Safety Climate	13	0	Positive	< 0.05
Safety compliance	13	2	Positive	< 0.01
Safety participation	13	0	Positive	< 0.01
Safety voice	3	1	Positive	< 0.01
Safety consciousness	4	0	Positive	< 0.05
Safety Behavior	4	0	Positive	< 0.01
Whistle-blowing behaviors	2	0	Positive	< 0.01
PPE Use Behavior	1	0	Positive	< 0.01
Near-miss recognition	1	0	Positive	< 0.05
Safety goal commitment	1	0	Positive	< 0.01
Safety citizenship behaviors	2	0	Positive	< 0.01
Safety initiative	1	0	Positive	< 0.01
Safety attitude	1	0	Positive	< 0.01
Risky behaviors	1	0	Negative	< 0.01
Injury	6	0	Negative	< 0.05
Safety-related events	5	0	Negative	< 0.01
Accident	2	0	Negative	< 0.01

The mechanisms through which SSTL affects safety outcomes

According to the findings presented in Table 3, previous studies extensively examined the direct and indirect relationships between SSTL and different safety outcomes. Based on these findings, various factors can mediate the relationship between SSTL and safety outcomes, remarkedly safety climate and safety motivation. Safety climate tremendously influences organizational safety [10]. The lack of a positive safety climate is a contributing factor to many major accidents [88, 89]. Moreover, safety climate can mediate and moderate the effect of many upstream functions on safety behavior and occupational accidents [90]. Safety motivation has also been recognized as an imperative determinant of safety performance [82]. As motivating subordinates is one of the most significant mechanisms using which transformational leadership attempts to accomplish its objective [24, 91, 92], safety motivation is a strong mediator between SSTL and safety performance.

Table 3.

The causal effect of SSTL on safety outcome

Relationship	Relationship type	Mediator Variable	Relevant Papers
SSTL → Safety climate	Direct	-	Cheung et al. [56], Shi and Zainal [55], Shi [60], Mirza and Isha [62], Cheung & Zhang [63], Smith et al. [39], Toderi et al. [70], Kelloway et al. [75], Barling et al. [35]
SSTL → Safety behavior	Direct	-	Mc Phee et al. [64], Wu et al. [40]
	Indirect	Harmonious safety passion	Wu et al. [40]
SSTL → Safety compliance	Direct	-	Xia et al. [58], DeArmond et al. [66], Mullen et al. [67], Smith et al. [39], Mullen et al. [73], Conchie [72], Nguyen et al. [54], Sivanathan et al. [47], Wang et al. [52]
	Indirect	Safety goal commitment	DeArmond et al. [66]
		Safety climate	Smith et al. [39]
		Identified regulation	Conchie [72]
SSTL → Safety participation	Direct	-	Xia et al. [58], DeArmond et al. [66], Mullen et al. [67], Smith et al. [39], Mullen et al. [73], Nguyen et al. [54], Sivanathan et al. [47] Wang et al. [52]
	Indirect	Safety goal commitment	DeArmond et al. [66]
		Safety climate	Smith et al. [39]
		Team safety motivation & Team safety climate	Wang et al. [52]
SSTL → Safety voice	Direct	-	Conchie [72]
	Indirect	Affect-based trust	Conchie [72]
		Intrinsic motivation	Conchie et al. [71]
SSTL → Safety consciousness	Direct	-	De Koster et al. [36], Kelloway et al. [75], Barling et al. [35]
SSTL → Whistle-blowing behaviors	Direct	-	Conchie [72]
	Indirect	Intrinsic motivation	Conchie [72]
SSTL → PPE use	Direct	-	Smith et al. [61]
	Indirect	Safety motivation	Smith et al. [61]
SSTL → Safety citizenship behaviors	Direct	-	Conchie & Donald [74], Usman et al. [51].
	Indirect	Safety specific trust	Conchie & Donald [74]
		Psychological contract fulfillment	Usman et al. [51]
SSTL → Safety goal commitment	Direct	-	DeArmond et al. [66]
SSTL → Near-miss recognition	Indirect	Employees’ performance goal orientation	Lu et al. [65]
SSTL → Mindful safety practices	Indirect	Safety motivation	Shi and Zainal [55]
		Safety climate	Shi [57]
		Safety climate	Shi [60]
SSTL → Safety attitude	Direct	-	Mullen et al. [67]
SSTL → Safety motivation	Direct	-	Shi and Zainal [55], Smith et al. [61]
SSTL → Safety-related events	Indirect	Safety consciousness and safety climate	Kelloway et al. [75]
		Safety consciousness and safety climate	Barling et al. [35].
SSTL → Accident	Direct	-	de Vries et al. [68], De Koster et al. [36]
	Indirect	Safety climate	Mirza and Isha [62]
SSTL → Injury	Indirect	Safety consciousness and safety climate	Kelloway et al. [75]
		Safety consciousness and safety climate	Barling et al. [35]

In two studies, Nguyen et al. [54] and Sivanathan et al. [47], researchers focused exclusively on the effect of SSTL on safety outcomes, without exploring the mechanisms behind that effect (whether direct or indirect). Nguyen et al. [54] aimed to distinguish between the effects of SSTL and GTL on safety, while Sivanathan et al. [47] conducted an interventional study intended to enhance safety behavior by improving SSTL. Additionally, two studies by Rafique et al. [59] and Mo et al. [53] investigated SSTL as both a moderating and mediating factor in the relationship between safety climate and safety behavior; however, both studies rejected these hypotheses.

Theories explaining the effects of SSTL on safety outcomes

Studies have employed various social, psychological, and organizational theories to explain both the direct and indirect effects of SSTL on safety outcomes. In total, nineteen studies (56% of the cases) used different theories to formulate their hypotheses or interpret their findings. The results are summarized in Table 4. As shown, the social exchange theory (SET) is the most commonly utilized theory, referenced by seven studies, followed by the leader-member exchange (LMX) theory, mentioned in three studies. Additionally, other theories have also been employed, as detailed in Table 4.

Table 4.

Basic theory for study design and conduction

Theory	Related Articles
Social-exchange theory	Smith et al. [61], Mirza and Isha [62], Cheung and Zhang [63], DeArmond et al. [66], Mullen et al. [67], Conchie et al. [71], Wu et al. [40]
Leader-member exchange theory	Shi [57], Shi [60], Lacerenza et al. [48]
Paradox theory	Nguyen et al. [54]
Social information processing theory	Cheung and Zhang [63]
Role theory	Cheung and Zhang [63]
Social learning theory	Cheung and Zhang [63], Wang et al. [52]
Organizational support theory	Cheung and Zhang [63]
Self-determination theory	Lu et al. [65]
Psychological contract theory	Mullen et al. [67], Usman et al. [51]
Higgins’ regulatory focus theory	de Vries et al. [68]
Self-determination theory	Conchie [72], Yang et al. [50]
High-Reliability Organization Theory	Shi and Zainal [55]
Situational strength theory	Xia et al. [58]
Trait activation theory	Mo et al. [53]

SET is one of the most important tools for understanding organizational behavior [93]. According to SET, employees are more inclined to comply with safety regulations and engage in safety-related activities when they perceive that their leaders genuinely care about their health and safety [41, 58, 61]. The principle of exchange, particularly the rule of reciprocity, is central to this theory; it suggests that relationships develop over time through various exchanges [93, 94]. There are six types of resources involved in these exchanges: love, status, information, money, goods, and services [95]. While research has not specified which resources contribute to SSTL, it appears that all resources except money and goods play a role in this context. It is important to note that money and goods are primarily associated with a transactional leadership style. Another significant theory is LMX, which emphasizes that leaders and employees develop relationships based on social exchanges [96]. Similar to SET, LMX asserts that a strong commitment to safety from leaders can enhance employees’ safety performance [57].

Safety specific transformational leadership versus other leadership styles

Eight studies have compared SSTL with other leadership styles. Table 5 presents a summary of these studies and their findings. Several of these studies have specifically compared SSTL with GTL. One significant finding is that SSTL and GTL are distinct constructs, even though they show a high level of correlation [54]. Overall, the impact of SSTL on safety outcomes tends to be slightly stronger than that of GTL.

Table 5.

A summary of studies comparing SSTL and other leadership styles in terms of their effects on safety outcomes

Article	A summary of findings
Nguyen et al. [54]	SSTL was compared to general transformational leadership (GTL) in two separate studies. In the first cross-sectional study, SSTL was found to be more effective in predicting safety compliance, while it showed only a slight advantage in predicting safety participation. The second study, which was time-lagged, divided participants into two groups based on their occupational settings: low-concern and high-concern. In the low-concern setting, there was no significant difference between GTL and SSTL in predicting safety outcomes. However, in high-concern settings, SSTL performed slightly better.
Shi [57]	SSTL was compared with safety-specific active transactional leadership (SSATaL) in terms of its effects on mindful safety practices (a variable very similar to safety participation). Both SSTL and ATL were significantly and positively related to mindful safety practices. SSATaL was a better predictor of mindful safety practices than SSTL.
McPhee et al. [64]	The moderating roles of SSTL and GTL on the relationship between safety climate and safety behavior were investigated. The results indicated that SSTL, and not GTL, moderates this relationship.
Lu et al. [65]	The study examined how SSTL and SSATaL influenced near-miss recognition, with safety climate acting as a moderator. Both styles positively impacted employees’ ability to recognize near misses.
Smith et al. [39]	The study examined how SSTL and Passive Leadership (PL) influence safety behaviors, with safety climate acting as a mediator, among a sample of American firefighters. The results showed that SSTL has a positive effect on the perceived safety climate, whereas PL negatively impacts the perceived safety climate and, as a result, diminishes safety behavior.
Toderi et al. [70]	SSTL was compared with passive leadership (PL) regarding their impact on safety climate. SSTL had a significant positive relationship with safety climate, while the effect of PL leadership was negative.
Mullen et al. [73]	SSTL was compared with PL in terms of its effects on safety compliance and safety participation in two studies conducted among young workers and adult workers. SSTL demonstrated a stronger association with both safety compliance and safety participation.
Kelloway et al. [75]	The effects of SSTL and PL on safety climate, safety awareness, and occurrences of safety events and injuries were compared. Both leadership styles significantly influenced safety outcomes, but their effects were opposite. Specifically, SSTL had a positive impact on safety outcomes, while PL had a negative impact.

Several studies, including Smith et al. [39], Toderi et al. [70], Mullen et al. [73], and Kelloway et al. [75], compared SSTL with the passive leadership (PL) style. These studies reported that the effect of SSTL on safety outcomes is significant and positive, while the effect of PL on these outcomes is significant and negative. This finding is consistent with previous studies as they mainly found a negative significant relationship between PL and safety and well-being [15, 97, 98].

Several studies, including those by Shi [57] and Lu et al. [65], have compared SSTL with Safety-Specific Active Transactional Leadership (SSATaL). Both SSTL and SSATaL have significant positive effects on safety outcomes, although SSATaL tends to have a slightly more powerful impact in some instances. It is important to note that transactional leadership relies on incentives, rewards, and punishments. As highlighted by Ghasemi et al. [99], these incentives may only impact safety outcomes in the short term. On the other hand, transformational leadership focuses on employees’ beliefs, values, and attitudes, suggesting that the effects of SSTL may last longer over time. Transactional leadership has faced criticism for its dependence on external motivations while often overlooking employees’ intrinsic beliefs and values [17]. Additionally, the outcomes associated with transactional leadership have been inconsistent in the literature. For instance, some studies indicate that this leadership style is linked to higher job satisfaction [100], while others report no such correlation [101].

Recommendations for future studies

Some research gaps present opportunities for future studies. Safety knowledge and safety motivation are well-recognized variables that mediate the impact of upstream factors on safety behavior and performance. Unlike safety motivation, studies have not scrutinized safety knowledge as a mediator in the relationship between SSTL and safety outcomes. Therefore, we recommend future research to consider this factor. SSTL is not likely to directly influence safety knowledge; instead, its influence may be mediated by other variables, such as safety training. Additionally, authentic leadership style has garnered considerable attention in recent years [21, 23]. However, previous studies have not investigated its effects on safety outcomes. Future studies should compare the impacts of SSTL and authentic leadership on leading and lagging safety indicators. Another research gap in this area is the lack of studies examining the buffering capacity of SSTL. Numerous variables can undermine safety in the workplace, including occupational fatigue, time and production pressure, and work-family imbalance. We hypothesize that SSTL may buffer the impact of these variables on safety; however, this topic requires further investigation in future studies. Lastly, as most studies have been conducted in a cross-sectional manner and such a study design is unable to infer causal relationships, it seems necessary to carry out longitudinal and interventional studies to provide more realistic results regarding the impacts of SSTL on safety outcomes.

Limitations

This study was the first scoping review conducted on SSTL. However, this study has some limitations that can be addressed in future studies. Although safety performance (including safety participation and safety compliance) safety behavior, incidents, and occupational injuries are the main leading and lagging safety indicators at workplaces, there may be other indicators that were not considered in this study, such as training courses, workers involvement, safety incentive systems, and so on. Moreover, this study focused on English papers, however, there was only one non-English record (which was not taken into account).

Conclusion

Sustainable Safety Transformational Leadership (SSTL) differs significantly from traditional transformational leadership, particularly in its positive impact on safety outcomes, especially safety behavior. Research has demonstrated the positive effects of SSTL across various workplaces and sectors. Therefore, managers should consider undergoing training to move away from passive leadership styles and adopt SSTL.

Two key variables through which SSTL influences safety behavior are safety climate and safety motivation. The relationship between SSTL and safety outcomes can be understood through social exchange theory. When compared to other leadership styles, SSTL is much more effective than passive leadership in enhancing workplace safety. Although safety-specific active transactional leadership may yield stronger short-term results, SSTL has more sustainable impacts on safety because it seeks to change employees’ beliefs and values.

The comparison between SSTL and authentic leadership is an interesting area for future research. Most studies in this field have been cross-sectional; hence, there is a need for more longitudinal studies to objectively demonstrate the long-term effects of SSTL on safety. Additionally, the potential of SSTL to mitigate the negative impacts of factors such as occupational fatigue, production pressure, and work-family imbalance has not yet been thoroughly explored.

Authors’ contributions

Fakhradin Ghasemi, Mohsen Mahdinia and Amin Doosti-Irani contributed equally to this work.

Funding

Abadan University of Medical Sciences have supported this study (Grant number: 1401U-1628).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

The study protocol is approved by the ethics committee of Abadan University of medical sciences (ethics code: IR.ABADANUMS.REC.1402.019).

Consent for publication

‘Not applicable’.

Competing interests

The authors declare no competing interests.