Transitioning Perspectives: Agile and Waterfall Perceptions in the Integration of Model-Based Systems Engineering (MBSE) within Aerospace and Defense Industries

The Aerospace and Defense (A&D) industry, known for its complexity, high-stakes, and stringent regulations, demands meticulous planning, testing, and adherence to established processes (Chang et al., 2016). Traditionally, the Waterfall methodology has been the norm for project management in this sector. Balaji & Murgaiyan (2012) describe the Waterfall model is a well-established linear design methodology, where progress flows sequentially downward through distinct phases, much like a waterfall. The common systems engineering (SE) V-model is considered an evolution of this waterfall approach, where the V-model alters the linear progression by bending the process steps upwards after the coding phase, creating a V-shaped structure (Balaji & Murugaiyan, 2012).

Despite its popularity, the Waterfall’s rigidity often fails to accommodate evolving requirements and market dynamics, leading to delays and cost overruns (Palmquist et al., 2013). Moreover, as subsystems and components become more complex, traditional document-based SE approaches become cumbersome, failing to meet organizational system development timelines (Kemp et al., 2015). Recognizing the need for change in SE, engineers proposed adopting and adapting Agile methods, which are traditionally used in software development, for SE (Beck et al., 2001). However, because Agile methods were initially designed for software, their direct application to SE was not straightforward (Carson, 2013). Agile coaches, therefore, emphasize the key principles of the Agile manifesto and provide strategies for scaling these methods within a large enterprise (Laanti, 2014).

Agile methodologies, which emphasize flexibility, collaboration, and iterative development, have emerged as promising alternatives. Despite considerable criticism, Agile methodologies have made a significant impact on software development (Meyer, 2014). Initially tailored for small teams (Meyer, 2014; Kahkonen, 2004; Beck, 2000; Paasivaara & Lassenius, 2016), their successful application has extended to larger-scale projects (Dikert et al., 2016; Lagerberg et al., 2013; Salo & Abrahamsson, 2008) and complex system development involving both software and hardware (Eklund et al., 2014; Berger & Eklund, 2015; Lagerberg et al., 2013). Many organizations are transitioning to Agile methodologies from the traditional Waterfall approach to enhance project efficiency, adaptability, and collaboration; claiming that this transition is critical in an industry where rapid technological advancements and evolving requirements demand a more iterative and flexible approach to project management (BAE Systems, n.d.).

The effectiveness of Agile methodologies can vary depending on the specific environment and type of project (Serrador & Pinto, 2015). Schatz & Abdelshafi (2005) described Primavera Systems’ successful shift to Agile development. A study by Akif et al. (2012) employed a survey to uncover key issues in implementing SCRUM, using two companies as case studies. Their survey revealed multiple challenges, including: accumulation of quality issues, problems with module integration, code quality concerns, disruptions in team collaboration, varying levels of SCRUM maturity, sprint duration issues, inadequate SCRUM training, difficulties in the release process, backlog management problems, absence of technical practices, coordination among multiple teams, metrics challenges, risk management issues, documentation problems, and overly idealistic expectations (Akif et al., 2012).

When looking at Agile software development with traditional developers and managers, two often conflicting views emerge. On one hand, Agile practices are seen as less onerous and more aligned with the industry’s demand for swift development and adaptation to ongoing changes, especially in smaller, independent projects. On the other hand, managers face several obstacles, both real and perceived, when attempting to introduce Agile methods into established organizations. These challenges are typically divided into issues related to scope and scale, or more general, systemic problems. There are three critical areas of concern: clashes in development processes, conflicts within business processes, and issues involving team dynamics. These are regarded as the major hurdles for software managers in large organizations trying to adopt Agile methodologies for their projects (Boehm & Turner, 2005).

The A&D industry is evolving, with diversified customer demands and stricter government regulations. Traditional organizations must adapt to remain competitive, often through Agile transformations (Hedlund & Ingo, 2018). Agile processes are now widely accepted in commercial industries, but for the Department of Defense (DoD), allowing software developers and end users to build, test, and release solutions with minimal oversight is a novel experience. In 2017, the DoD initiated a significant change by replacing an ineffective, costly software acquisition process with the Agile model (Kenner, 2019). Bieler (2012) evaluated the transformation towards Agile of the US Air Force (USAF). They described how USAF has struggled to develop state-of-the-art systems quickly, which is important to meet the needs of warfighters; hence USAF has been transitioning from a Waterfall to an Agile approach for software acquisitions, but progress has been slow. A key finding of Beiler (2012) is that while USAF faces challenges similar to those of large corporations, its unique stakeholders require tailored solutions and that successfully implementing Agile could help organizations deploy needed systems more effectively. Adopting a holistic view will better equip companies to overcome current Agile transformation challenges and deliver critical capabilities to warfighters (Bieler, 2018). Such environments, characterized by lengthy lead times (Berger & Eklund, 2015) and established, sequential engineering practices (Pernstål et al., 2012), often present challenges. These challenges include defining product value, clarifying product purpose, addressing cross-cutting concerns (Kasauli et al., 2021), and managing requirements (Savolainen et al., 2010). Due to these difficulties, organizations frequently find it challenging to implement effective Agile within a large-scale project (Laanti et al., 2011; Wiklund et al., 2013; Chow & Cao, 2008). Research on challenges related to Agile methodologies primarily emphasizes the development of new methods, practices, and artifacts (Heikkilä et al., 2017).

Several studies address the challenges and difficulties encountered during the transition to Agile methodologies. These challenges are generally categorized into four main areas: (i) organization and management; (ii) people; (iii) process; and (iv) tools (Gandomai et al., 2013). Although these issues can vary between organizations, they need to be thoroughly analyzed and addressed (Gandomai et al., 2013). Another study identifies three primary categories of challenges: (i) culture; (ii) team practices; and (iii) scaling (Gregory et al., 2015). Furthermore, research by Hamid et. al (2015) highlights key factors hindering the adoption of Agile practices in the software industry, including: (i) heavy reliance on personnel; (ii) organizational dependencies; and (iii) significant impacts on organizational structure and culture. Finally, another study notes that the primary challenge in implementing Agile software development lies in adapting to evolving needs and requirements to meet customer expectations, rather than adhering strictly to predefined practices (Ganesh & Thangasamy, 2012).

Research on best practices for adopting Agile methodologies is another key area of interest. The theory of Complex Adaptive Systems (CAS) can provide insights into how Agile software development practices can be optimized by examining the three dimensions of CAS: product, process, and people (Meso & Jain, 2006). Another study (Tanner & Willingh, 2014) explores the factors influencing the success or failure of Agile projects, particularly when transitioning from traditional waterfall environments. Six key factors were identified: (i) organizational culture; (ii) customer engagement and mandate; (iii) stakeholder participation and buy-in; (iv) team structure and logistics; (v) project type and planning; and (vi) the skills and attitudes of team members. Additionally, practical applications of Agile have sometimes deviated from the principles outlined in the Agile Manifesto, potentially limiting the realization of its intended benefits (West, 2011).

Model-Based Systems Engineering (MBSE) has emerged as a viable approach for the design, verification, and validation of complex, safety critical systems, such as those within the scope of A&D applications. It provides a structured methodology that integrates modeling into system engineering processes to enhance the precision, traceability, and collaboration across the system’s lifecycle. As defined by INCOSE, “MBSE is the formalized application of modeling to support system requirements, design, analysis, verification, and validation throughout the system’s life cycle” (Walden et al., 2015). The approach includes a set of interlinked processes, techniques, and tools functioning within a model-based or model-driven context, that has proven to be an effective approach for designing, verifying, and validating complex, safety-critical systems, such as those in aerospace and defense (Estefan, 2008). Companies have embraced MBSE to improve the development and testing of complex systems. When combined with Agile methodologies, MBSE enhances system engineering efficiency by ensuring transparency and traceability, accelerating the delivery of engineering artifacts, and applying decades of research and experience to modern systems, thereby improving their performance and development outcomes (Call & Herber, 2023). As depicted in Figure 1, which was adapted from Call & Herber (2023) and Madni & Purohit (2019), the growing complexity of interactions typical in a traditional, document-based approach can be streamlined by allowing stakeholders to directly input and retrieve SE data within the model itself.

Figure 1: Visualization of traditional systems engineering (SE) and model-based systems engineering (MBSE) adapted from Call & Herber (2023) and Madni & Purohit (2019)

Industries such as aerospace and software development have adopted MBSE methods to enhance the development of intricate systems and products, including testing; through MBSE methodologies, abstract models representing real-world scenarios can be generated (Bradley & Alvarado, 2023; Mussa et al., 2009). The integration of MBSE in Agile has been found to further enhance understanding and effectiveness. The Agile requirements analysis process, coupled with MBSE, offers a means for organizations to enhance the efficiency of the systems engineering process. It achieves this by ensuring transparency and traceability of information, expediting the delivery of systems engineering artifacts (Huss et al., 2023). A deeper comprehension about MBSE can lead to better outcomes. Agile systems engineering, supported by MBSE, serves as the vital link that enables the principles and processes developed over decades of research and experience to be effectively applied to modern systems, enhancing their development and performance (Call & Herber, 2023).

Moreover, involving customers throughout the process ensures a comprehensive understanding and early addressing of requirements in the systems’ development lifecycle (Smith & Castro, 2018). Successful MBSE implementation necessitates the seamless integration of models, datasets, tools, and infrastructure with relevant processes, methods, and standards, forming a comprehensive and integrated MBSE system. MBSE synchronizes diverse organizational, technical, and temporal perspectives through a common backbone – a comprehensive, integrated set of system models crafted using a robust modeling language like the Systems Modeling Language (SysML) (Noguchi et al., 2020). Traditional MBSE techniques define high-level requirements, while Agile methodologies are used for developing software models. This hybrid methodology leverages both MBSE and Agile practices to manage evolving, complex system simulation capabilities, enhancing requirements definition and integration (Power et al., 2021).

The primary objective of this paper is to examine the role of MBSE in facilitating the transition from Waterfall to Agile methodologies, with a focus on its impact on project management processes, efficiency, and time-to-market. Additionally, the paper aims to identify the success factors and limitations associated with MBSE implementation during this transition. Existing literature provides a foundation for understanding MBSE within Agile frameworks, but there is a significant research gap concerning its integration and role in facilitating the transition from traditional Waterfall methodologies to Agile. This paper focuses on the outcomes of a comprehensive survey aimed at examining how MBSE supports this transition in the A&D sector. By analyzing its impact on both frameworks, the study highlights the challenges of shifting from Waterfall to Agile and how MBSE can bridge the gap, enhancing efficiency and adaptability during the transition. There is a need to derive the research-based best practices for integrating MBSE. Firstly, there is a notable gap in understanding how MBSE integrates with and impacts traditional Waterfall models, encompassing aspects such as project timelines, resource utilization, and overall efficiency. The paper includes research on the practical implementation of MBSE in Agile environments, particularly in terms of exploring the synergies, challenges, and effects on project success. Additionally, there is a need for research that delves into the comparative effectiveness of MBSE in enhancing communication, collaboration and project outcomes within the distinct contexts of Waterfall and Agile methodologies. With advances in MBSE, new techniques have been proposed to transition from document-based to model-based paradigms using standardized modeling languages. However, current methods may lack sufficient traceability for integration with other system lifecycle activities (Cutajar & Ji, 2023). Addressing these research gaps will provide valuable insights into optimizing MBSE practices and facilitating informed decision-making for project management strategies. Through these research gaps, this paper contributes to optimizing MBSE practices and facilitating informed decision-making in project management within the aerospace and defense sectors.

An online survey was conducted for this study. The survey was approved by the Institutional Review Board (IRB) at Colorado State University.

A. PARTICIPANTS

There was a total of 40 participants that completed the survey. The study surveyed employees from BAE Systems, a prominent defense and aerospace company. BAE Systems, known for its significant contributions to defense, security, and aerospace industry, is an ideal setting for this study due to its ongoing transition from traditional Waterfall methodologies to more flexible Agile practices. This provides a rich context for exploring the practical implications, challenges, and benefits of Agile practices in a highly regulated and technologically complex industry. The insights gained from BAE Systems employees can offer valuable lessons and best practices that can be applied across the A&D sector, aiding other organizations in navigating similar transitions. Participants were recruited from various departments within BAE Systems across the United States, seeking diverse representation of experiences and perspectives. This recruitment process aimed to capture a comprehensive understanding of how Agile methodologies are being implemented and perceived across different project types and stages.

All participants were selected based on their current or past roles as software or systems engineers and/or Agile-related job responsibilities. This focus ensures that the insights gathered are directly relevant to the technical and project management challenges inherent in the A&D industry.

B. SURVEY DESIGN

The survey was conducted online through SurveyMonkey. Data collection occurred March through August 2024. It took participants, on average, 10 minutes to complete the survey. Participation was both anonymous and voluntary, encouraging candid responses and ensuring that the data collected accurately reflects the participants’ genuine experiences about the current and past projects. The anonymity of the survey was crucial in obtaining honest feedback, free from the potential biases or fears of repercussions.

The survey was designed to capture insights from professionals actively engaged in A&D projects at BAE Systems, focusing on their roles, experience levels, and the specific methodologies employed. Participants provided detailed responses regarding the perceived effectiveness and challenges of Agile practices when integrated with MBSE. The survey consisted of several sections. The first section captured participants’ roles, experience with Agile and Waterfall methodologies, and overall tenure in systems or software development. Then captured 5-point Likert scale data on attitudes towards Agile practices and experience with various practical applications of Agile methods (e.g., Scrum, Kanban, and Extreme Programming, XP). The survey then captured integration of MBSE into Agile projects, including the challenges, successes, and perceived effectiveness of MBSE in managing requirements. Lastly, there was an open-ended question for deeper qualitative insights. These survey questions were developed based on gaps in knowledge and challenges of implementation identified in our literature review.

A. PARTICIPANT JOB POSITIONS

The participants in the survey represented a diverse array of job roles, reflecting the multifaceted nature of project teams. Note, participants could select more than one job role, which several did. As shown in Table 1, the most prevalent job role was engineer, comprising 31.7% (N=19) of the total participants. These include software or system engineers, who play a crucial role in A&D projects, contributing their technical expertise to various aspects of system and software development. Next were Team Leads, who are responsible for overseeing project teams, coordinating activities, and ensuring project objectives are met within specified timelines and budgets. Then, Product Owners, Developers, and Designers each represented significant proportions of the participant pool. Product Owners are tasked with defining and prioritizing project requirements from a stakeholder perspective, while Developers and Designers are involved in the implementation and design aspects, contributing to the development of software and system components. Scrum Masters, Testers, and Business Stakeholders were also represented among the survey participants. Scrum Masters facilitate the adoption of Agile practices within project teams, ensuring adherence to Agile principles and facilitating collaboration and communication. Testers play a critical role in quality assurance, conducting thorough testing to validate system functionality and performance. Business Stakeholders provide valuable insights into project requirements and priorities from a business perspective, guiding decision-making and project direction.

Table 1. Survey Participants’ Job Roles on Project Teams

Position	Count	Percentage
Engineer	19	31.7
Team Lead	9	15
Product Owner	5	8.3
Developer	7	11.7
Scrum Master	8	13.3
Designer	6	10
Business Stakeholder	2	3.3
Tester	3	5
Agile Coach	1	1.7

 

B. EXPERIENCE WITH AGILE AND WATERFALL PRACTICES

The survey revealed a diverse range of experience with Agile practices. Participants reported experience ranging from 1 to 20 years, with a mean of 5.07 (SD = 3.78). These upper values indicate that many participants have substantial experience and insights into Agile methodologies. Notably, one participant reported 20 years of experience. Additionally, experience durations of 3 and 5 years were also common, showing a mix of moderate and more recent adopters. This diversity in experience levels contributes to a comprehensive understanding of Agile utilization in A&D projects.

Similarly, participants provided a wide range of experience with Waterfall practices, from 1 to over 40 years and mean of 7.07 (SD = 7.46). Those with shorter tenures, around 1 year, likely reflect recent transitions to Agile or hybrid methodologies. Participants with 9 to 12 years of experience have practical insights into the successes and challenges of Waterfall projects. Extensive experience, surpassing 15 years and even up to 40 years, indicates deep-rooted familiarity with Waterfall methodologies, reflecting its historical dominance in the industry. This variation underscores differing perspectives on project management approaches and the potential benefits of integrating newer methodologies like Agile.

C. ADOPTION OF AGILE, HYBRID, AND WATERFALL

Participants were asked to rate their team’s use of Agile practices on a scale from 0 to 100, where 0 represents all Agile, 50 represents a hybrid approach, and 100 represents all Waterfall, see Table 2. The data collected indicates a diverse range of practices, with mean of 48.83 and a standard deviation of 16.28. The scores ranged from a low of 0 to a high of 70. Most teams positioned themselves closer to the hybrid model, specifically within the 50 to 70 range, suggesting a blend of Agile and Waterfall methodologies. This trend indicates that while Agile practices are being integrated to enhance flexibility and efficiency, the structured nature of Waterfall remains necessary for meeting stringent requirements and regulatory standards. Some teams are fully embracing Agile principles, while others still rely significantly on traditional Waterfall practices, reflecting the transitional nature of project management methodologies at BAE Systems.

Table 2. Use of Agile Practices, from 0 (all Agile) to 100 (all Waterfall)

Descriptive Statistic	Value
Mean	48.83
Standard Deviation	16.28
Range	0 to 70

The mean score of 48.83 indicates that, on average, teams at BAE Systems lean towards Agile methodologies but have not fully embraced them. This score suggests that most teams are adopting a hybrid approach that combines Agile practices with elements of Waterfall methodology. The standard deviation of 16.28 further highlights the variability in how different teams implement Agile practices, pointing to a wide range of adoption levels and practices within the organization. The analysis of Agile practice ratings reveals several key insights about the project management practices at BAE Systems. Firstly, the high mean score and the prevalence of hybrid approaches underscore the organization’s pragmatic strategy of integrating Agile methodologies with traditional Waterfall practices. This integration allows teams to leverage the benefits of Agile’s flexibility and iterative processes while addressing the need for structured planning and documentation. Secondly, the variability in scores and the presence of both fully Agile and predominantly Waterfall teams highlight the transitional nature of project management practices within the organization. Some teams have fully embraced Agile principles, benefiting from its adaptive approach, while others continue to rely heavily on Waterfall methods due to their suitability for certain types of projects. This transitional phase reflects the ongoing evolution in project management strategies at BAE Systems, as the organization seeks to balance flexibility with regulatory compliance. Thirdly, the trend towards hybrid approaches illustrates the organization’s ability to tailor its project management practices to the specific needs and challenges of different projects. This tailored approach enables teams to optimize their methodologies, combining Agile’s advantages with the necessary structure provided by Waterfall. It also highlights the importance of flexibility in project management, as teams adapt their practices to achieve the best outcomes for their projects. The survey results provide valuable insights into the application of Agile and Waterfall methodologies at BAE Systems. The trend towards hybrid practices reflects a strategic balance between flexibility and structure, allowing teams to effectively manage complex projects. Understanding this balance is crucial for optimizing project management practices and ensuring successful project outcomes in a dynamic and regulated environment.

D. PERCEIVED BENEFITS OF AGILE METHODOLOGIES

Agile methodologies have gained significant traction due to their emphasis on flexibility, collaboration, and iterative progress. Understanding the acceptance and perceived effectiveness of Agile practices among employees is crucial for companies aiming to implement or refine their Agile processes. Participants were asked about their attitudes towards Agile acceptance, including responsibility completion, alignment with working style, effectiveness, quality of work, flexibility, compatibility, and control over work, see Figure 2. The survey data reveals a strong positive attitude towards Agile practices among employees surveyed. Specifically, 73% of participants agree/ strongly agree that Agile methodologies are beneficial overall. A significant 85% agree/ strongly agree that Agile enables flexibility in tasks, though only 34% find it compatible with all work facets. Additionally, 73% believe that Agile practices give them more control over their work, showcasing the overall positive reception of Agile methodologies within the company.

Figure 2: Perceptions of participants regarding implementing Agile methodologies on the team. It shows a broad range of opinions with a significant number of respondents expressing positive views.

The analysis in Figure 3 below presents survey results on the effectiveness and implementation of Agile methodologies observed among the participants. A majority 78% of participants believe that Agile positively impacts their work. Notably, 62% of participants agree/ strongly agree that using proper tools facilitates effective Agile usage. However, there are concerns regarding training, as 38% of participants feel that their management did not provide adequate training for Agile practices. These findings highlight the general effectiveness of Agile practices within BAE Systems, while also pointing out areas for improvement, particularly in management training and tool utilization, to further optimize Agile implementation.

Figure 3: Perceived impact of Agile methodologies on project outcomes. It indicates positive views on proper tools usage, however, there is room for improvement in training efforts from management.

The data in Figures 2 and 3 were further analyzed to compare perceptions between Agile and Waterfall adoption within teams (as described in the section above “Adoption of Agile, Hybrid, And Waterfall”), where participants who were mostly practicing Agile (< 50) and mostly practicing Waterfall (> 50) were compared. Note, these questions were on a 5-point Likert scale of agreement, where responses above 2.5 are favorable towards agreement and below 2.5 represent disagreement towards the statement as shown in Table 3. The survey results highlight a generally positive attitude toward Agile practices among employees across different teams, regardless of whether they primarily adopt Agile or Waterfall methodologies. Employees who mostly practice Agile tend to rate Agile’s effectiveness slightly higher on certain statements, such as “Using Agile matches my preferred working style” (mean = 4.12, SD = 0.64) and “Agile allows me to have more control over my work” (mean = 4.12, SD = 0.64), compared to those mostly using Waterfall who rated these statements at 3.91 (SD = 0.79) and 3.52 (SD = 1.03), respectively. This suggests that Agile adopters may feel a stronger alignment between Agile practices and their work style, as well as a greater sense of control over their tasks.

Across both groups, statements regarding the flexibility and productivity enabled by Agile received favorable ratings, with the overall mean for “Agile enables some flexibility in my current tasks” at 4.00 (SD = 0.67) and “Agile has made me more productive and efficient in my daily tasks” at 3.94 (SD = 0.71). These high ratings indicate broad agreement on Agile’s role in enhancing task flexibility and efficiency, even among those who primarily practice Waterfall.

Interestingly, while both groups reported positive experiences with Agile, differences emerge in perceptions of training and compatibility. Participants primarily practicing Agile rated “Management has provided adequate training to use Agile practices effectively” slightly lower (mean = 3.00, SD = 0.92) than those mostly practicing Waterfall (mean = 3.39, SD = 0.99), which may reflect a perceived need for more formalized Agile training among Agile-focused teams. Additionally, the statement “Agile is compatible for all facets of my work” received mixed ratings, with a lower mean among mostly Waterfall teams (mean = 2.73, SD = 1.00), suggesting that these teams may face challenges integrating Agile into certain aspects of their work. Overall, the survey results underscore the positive reception of Agile practices across different experience levels, though there are areas—particularly in training and full compatibility—where further support may enhance Agile adoption and effectiveness in the workplace.

Table 3. Perceived Impacts (5-point Likert scale) of Agile based on Participants Experience Level

Agile Impact Statement	Overall Mean (SD)	Mostly Agile Mean (SD)	Mostly Waterfall Mean (SD)
I can complete my responsibilities quickly by implementing Agile practices	3.72 (0.65)	3.62 (0.74)	3.78 (0.67)
Using Agile matches my preferred working style	3.92 (0.77)	4.12 (0.64)	3.91 (0.79)
Agile increases my effectiveness at work	3.94 (0.82)	4.00 (1.07)	3.95 (0.82)
I can produce better quality by implementing Agile practices	3.78 (0.79)	3.75 (1.03)	3.83 (0.72)
Agile enables some flexibility in my current tasks	4.00 (0.67)	4.12 (0.35)	4.04 (0.63)
Agile is compatible for all facets of my work	2.86 (1.01)	3.00 (0.92)	2.73 (1.00)
Agile allows me to have more control over my work	3.77 (0.93)	4.12 (0.64)	3.52 (1.03)
Using proper tools allow for effective agile usage	4.11 (0.57)	4.50 (0.76)	3.95 (0.47)
Management has provided adequate training to use agile practices effectively	3.28 (0.97)	3.00 (0.92)	3.39 (0.99)
Agile predicts the work required in the project	3.86 (0.68)	3.87 (0.99)	3.91 (0.51)
Agile has reduced the number of errors in my tasks	3.61 (0.84)	3.37 (1.06)	3.78 (0.67)
Agile has made me more productive and efficient in my daily tasks	3.94 (0.71)	3.87 (0.64)	4.00 (0.60)
My customers are satisfied with the functionality of the products since implementing agile	3.97 (0.65)	4.00 (0.53)	4.04 (0.70)

The analysis presented in Table 3 provides a nuanced view of survey results concerning the effectiveness and implementation of Agile methodologies within the organization. The data reveal several key insights into the participants’ perceptions and experiences with Agile practices, shedding light on both the strengths and potential areas for improvement in the Agile adoption process. These findings collectively highlight the overall effectiveness of Agile methodologies within BAE Systems, as perceived by the participants. However, the mixed responses concerning training and tool utilization signal areas that require further attention. To optimize Agile practices, it is crucial to address the identified training gaps by enhancing training programs to ensure comprehensive preparation for all employees. Additionally, the emphasis on proper tool utilization suggests a need for ongoing investment or refinement in technological support to better align with Agile workflows. By addressing these areas, the organization can enhance the effectiveness of Agile implementation and fully leverage its benefits.

These results provide valuable insights into the current state of Agile methodologies within the organization. The positive overall perception of Agile, combined with concerns about training and tool utilization, offers a foundation for targeted improvements. To successfully transition from Waterfall to Agile, a significant organizational mindset change is required, including leadership buy-in. Leadership support is critical to driving cultural shifts, ensuring alignment across teams, and allocating resources to support Agile practices. By focusing on enhancing training programs and optimizing tool use, the organization can better support Agile practices and achieve more effective project management outcomes.

E. AGILE IMPLEMENTATION ON TEAMS

Participants were asked what Agile methods they actively use, allowing them to select all that apply. The survey results reveal a clear preference for Scrum and Kanban among participants, as shown in Figure 4, highlighting their perceived effectiveness in managing complex, high-stakes projects at BAE Systems. This question was structured as multiple-choice, allowing respondents to select all that they actively use. Scrum emerged as the most widely used methodology, with 77.5% (N = 31) of participants selecting it, reflecting its structured yet flexible framework, which is particularly valuable in project environments requiring iterative sprints and continuous improvement. Scrum’s approach to breaking down large tasks into manageable increments aligns well with BAE Systems’ focus on rigorous project management and quality control. Additionally, Scrum’s emphasis on team roles and regular feedback loops helps maintain alignment and ensures swift adjustments to meet project demands. Agile Modeling followed closely, with 55% (N = 22) of respondents indicating its use. Agile Modeling emphasizes visual management and a continuous workflow, facilitating real-time adjustments and promoting transparency—a critical need in regulated, high-visibility sectors such as aerospace and defense. This methodology supports the need for precise tracking and adaptability, making it an effective choice for project managers who must balance innovation with regulatory compliance.

Notably, participants reported using hybrid approaches that combine elements from different Agile methodologies, such as Scrum and Extreme Programming (XP). This adaptability speaks to Agile’s inherent flexibility and participants’ ability to tailor practices to the specific demands of their projects. For instance, incorporating XP’s emphasis on technical practices, like test-driven development, into Scrum’s iterative framework can enhance code quality and stability, addressing the stringent standards often required in defense contracts.

The survey revealed that participants employed hybrid approaches, integrating elements from various Agile methodologies such as Scrum and Extreme Programming (XP). This hybridization demonstrates the flexibility and adaptability inherent in Agile practices, allowing teams to customize their methodologies to align with the specific needs and challenges of their projects. For instance, combining Scrum’s structured sprints with XP’s focus on technical excellence can create a robust framework that addresses both project management and technical requirements effectively. This tailored approach enables teams to optimize their methodologies to achieve better alignment with project goals and enhance overall project performance. The survey results reflect a strategic alignment between Agile methodologies and the needs of high-stakes projects at BAE Systems. The combination of Scrum, Kanban, Agile Modeling, Lean practices, and hybrid approaches provides a comprehensive toolkit for managing complex projects effectively. These methodologies collectively contribute to enhanced project performance, flexibility, and responsiveness, demonstrating their value in addressing the organization’s project management challenges. The preference for Scrum and Kanban, coupled with the use of Agile Modeling and Lean practices, underscores a sophisticated approach to Agile implementation at BAE Systems. The incorporation of hybrid methodologies further illustrates the organization’s commitment to optimizing project management practices and adapting Agile principles to achieve superior project outcomes.

Figure 4: Most popular Agile methods used among survey participants. It highlights the diverse approaches utilized within the Agile framework, showcasing preferences that can inform best practices in project management.

The survey also highlights a range of management tools used by professionals to ensure efficient workflow and project management. Participants were able to select multiple answers. The data reveals preferences for specific tools, indicating their perceived effectiveness and usability. Figure 5 highlights the prevalent use of various management tools within the company. Atlassian tools (82.5%) and Kanban boards (80%) are the most widely used, reflecting their effectiveness in supporting Agile project management through visualization, collaboration, and comprehensive tracking. GitLab is also used by 30% of participants for source code management. Other tools include custom-developed internal tools (12.5%), unit test tools (15%), and spreadsheets (17.5%), indicating a mix of standardized and tailored approaches to project management. The multiple tools usage shows the company’s commitment to leveraging technology to optimize workflows, improve communication, and ensure project success.

The variety of tools used within BAE Systems demonstrates the company’s commitment to leveraging technology to optimize project management workflows and enhance communication. The high adoption rates of Atlassian tools and Kanban boards highlight their effectiveness in supporting Agile project management, suggesting that these tools play a central role in facilitating iterative development and real-time progress tracking. The diverse tool usage underscores the need for tailored solutions while emphasizing the importance of ongoing optimization to achieve maximum effectiveness and efficiency in project management practices.

Figure 5: Most widely used Agile tools among survey participants. The results provide insights into the tools that facilitate Agile practices.

F. MBSE INTEGRATION

This section explores the extent to which MBSE has been integrated into Agile projects based on survey responses. Participants were asked whether they had integrated MBSE into any of their Agile projects. The results indicate a strong inclination towards the integration of MBSE in Agile projects, with a significant majority (78.3%) affirming its use. However, the remaining participants who have not integrated MBSE into their Agile projects suggest that there are still challenges and barriers to adoption. The results show the growing trend of integrating MBSE into Agile projects, driven by the complementary strengths of both methodologies. The results also indicate that a significant majority of participants find MBSE to be effective (74.36%) in Agile environments. The survey highlights that MBSE is viewed as an effective method for capturing and managing requirements in Agile projects. Participants rated MBSE implementation on their teams on a scale from 0 to 100, with a mean score of 55.82 and standard deviation of 16.38. This variability suggests that while some teams have successfully integrated MBSE into their Agile practices, others are still navigating the complexities of adoption. Tailoring implementation strategies and providing targeted support can help address these disparities and enhance overall effectiveness.

The strong inclination towards integrating MBSE into Agile projects highlights a growing recognition of the value that MBSE brings to Agile environments. The ability of MBSE to provide a structured approach to capturing and managing complex requirements complements Agile’s iterative and adaptive processes. The term “complex requirements” in this journal aligns with the INCOSE definition, which highlights factors such as the number of interrelated system elements, the degree of interdependence among them, and the dynamic interactions within and between systems. Complex requirements often involve high interconnectivity, where changes in one component can affect others, and they may be subject to evolving stakeholder needs or technological shifts. Additionally, these requirements can be ambiguous or uncertain at the outset, requiring iterative refinement (Walden et al. 2015). The fact that 78.3% of participants have integrated MBSE suggests that many teams are leveraging its capabilities to enhance their Agile practices, particularly in areas such as requirements management, system modeling, and verification. Despite this positive trend, the remaining participants who have not integrated MBSE into their Agile projects indicate that challenges and barriers to adoption still exist. These obstacles may include issues related to tool compatibility, the complexity of MBSE methodologies, or resistance to change within teams accustomed to traditional practices. Addressing these barriers will be crucial for further adoption and effective utilization of MBSE in Agile contexts.

G. PARTICIPANTS’ COMMENTS ON MBSE AND AGILE IMPLEMENTATION

The survey gathered insightful comments from participants on the integration of MBSE and Agile methodologies, highlighting their impact on workflow, efficiency, and team dynamics. A summary of these comments is provided below, corresponding to themes:

• Enhanced Workflow and Efficiency: Many participants noted that incorporating MBSE and Agile significantly enhanced their workflow and efficiency. They reported that MBSE enabled the creation of precise, visual models that improved system understanding and facilitated better communication with stakeholders. This reduction in ambiguities and rework, coupled with Agile’s iterative development and continuous feedback, helped teams stay adaptable and aligned with evolving requirements.
• Challenges with Agile Implementation: Some participants expressed concerns about the proper implementation of Agile. They pointed out that resistance from management, who prefer traditional Waterfall processes, can hinder Agile’s effectiveness.
• Impact of Scrum Practices: Opinions were mixed regarding Scrum practices. While some participants acknowledged that Scrum processes improved productivity and communication, others found daily scrums overbearing and counterproductive. This suggests a need for balance in implementing Scrum to avoid potential negative impacts on team morale and efficiency.
• Use of Additional Tools: Participants mentioned the use of various tools such as Tableau, Power BI, and Oracle in their Agile processes. These tools complemented MBSE and Agile methodologies by facilitating data analysis and project management tasks.
• Role of Leadership and Training: The importance of experienced and pragmatic leadership in using MBSE tools effectively was emphasized. Knowing when to use specific tools and when to avoid them is crucial for successful Agile implementation. Additionally, several participants highlighted the need for more initial training in Agile methodologies. They believed that better training would have given their teams a clearer understanding of Agile’s benefits and how to implement it effectively.
• Quality and Integration Risks: Some participants pointed out that while Agile can speed up certain engineering processes, the quality of the output heavily depends on the skills of the individuals involved. They noted that Agile teams might introduce risks into complex integration efforts. These risks often manifest later in the project lifecycle, potentially leading to costly fixes. The complexity of projects can make Agile less efficient compared to simpler, faster-paced environments like software development.

Overall, the comments reflect a refined perspective on the integration of MBSE and Agile methodologies. While participants recognize the benefits of these approaches in improving workflow and efficiency, they also highlight significant challenges and areas for improvement, particularly in management support, training, and balancing Agile practices to suit complex project environments.

The survey results highlight the acceptance and implementation of Agile methodologies. In companies such as BAE Systems, where projects often involve intricate systems and interdependencies, Agile modeling helps teams visualize and manage complexity effectively. This is supported by the literature, where Agile methodologies such as Scrum and XP, initially designed for smaller projects (Kahkonen, 2004; Beck, 2000; Paasivaara et al., 2016), are increasingly being implemented in large-scale system development organizations (Salo & Abrahamsson, 2008). Participants from diverse roles, including product owners and engineers, generally reported improved efficiency, flexibility, and customer satisfaction with Agile practices. However, our survey respondents, as well as others in the literature such as Palmquist et al. (2013), describe challenges that remain in balancing Agile’s iterative processes with MBSE’s upfront modeling requirements. The adoption and success of MBSE may be hindered by a lack of widespread understanding within the systems engineering community regarding its precise definition. This ambiguity often leads to ineffective implementations. Early modeling, particularly in MBSE, plays a critical role in iterative development by enabling simulations that refine and validate requirements throughout the project life cycle. These simulations not only facilitate early detection of issues but also enhance the adaptability of the requirements definition process, ensuring alignment with Agile’s iterative approach. By leveraging MBSE’s capabilities for continuous validation, organizations can streamline requirement development and reduce rework, thereby supporting project efficiency rather than hindering it.

The survey results regarding participants’ experience with both Agile and Waterfall methodologies highlight critical insights into the challenges of transitioning from Waterfall to Agile in the A&D sector. This range of experience levels—from a few years to several decades—indicates that organizations often find themselves in a hybrid state, caught between the established, document-heavy Waterfall approach and the iterative, collaborative Agile methodology. Participants with extensive Waterfall experience (over 15 years, up to 40 years) may naturally gravitate towards familiar processes, making them hesitant to fully embrace Agile principles. This entrenchment creates significant roadblocks when trying to foster Agile mindsets within teams. Waterfall’s rigid structure can be comforting for those accustomed to it, but its inflexibility hampers the adaptability required for modern systems engineering, especially when managing rapidly evolving requirements typical of A&D projects. Conversely, participants with Agile experience of 2 to 20 years provide insight into Agile’s benefits but may still face institutional resistance from those more comfortable with Waterfall practices. The survey reveals that, despite the push towards Agile, many organizations still operate within a hybrid framework. In such settings, teams are often required to adhere to both Waterfall’s hierarchical documentation requirements and Agile’s iterative, flexible cycles, which can lead to conflicts in project goals, resource allocation, and decision-making.

The hybrid approach is particularly detrimental because it can diminish the full potential of Agile methodologies. Agile’s strength lies in its ability to enhance collaboration, responsiveness, and iterative problem-solving. However, when teams are forced to toggle between Waterfall’s linear stages and Agile’s iterative sprints, project timelines can be delayed, communication between teams may become fragmented, and innovation stifled. This is supported in Davis (2012), who reported that the presence of different mindsets within the same organization can further exacerbate these issues, leading to misaligned priorities, increased inefficiencies, and a lack of cohesion across teams.

Ultimately, the data suggests that transitioning fully to Agile methodologies in A&D requires not just training in Agile principles, but a cultural shift that embraces Agile’s inherent flexibility. Failure to do so risks the organization becoming “stuck” in a hybrid state, which can lead to a suboptimal combination of both methodologies, causing confusion and limiting the benefits that Agile could provide to improving systems engineering and project management outcomes. Organizations must recognize these challenges and invest in a deliberate and systematic shift toward Agile practices, breaking away from legacy systems that may no longer serve the needs of complex modern projects.

In A&D organizations transitioning from Waterfall to Agile, the hybrid project management environment can pose significant challenges. While Agile practices offer increased flexibility, autonomy, and iterative progress, their coexistence with traditional methodologies such as Waterfall can cause friction. Agile thrives in environments where quick iterations, adaptability, and collaborative processes are valued. However, Waterfall’s linear, document-driven, and often rigid nature can inhibit the full potential of Agile’s iterative benefits. The result is that employees can struggle to seamlessly switch between Agile’s fast-paced, adaptive approach and Waterfall’s highly structured phases.

In organizations where Agile is layered onto existing Waterfall processes without full integration, the hybrid setup can lead to operational inefficiencies. For example, employees might be expected to generate comprehensive documentation (typical of Waterfall) while simultaneously performing iterative updates (characteristic of Agile), causing task duplication and a slowdown in project velocity. Additionally, team members may experience confusion regarding their roles and responsibilities, as Agile encourages shared ownership and rapid decision-making, which contradicts the hierarchical, approval-heavy processes of Waterfall.

Further complicating this hybrid dynamic is the notion that Agile is not universally applicable to all work facets. This limitation can contribute to operational bottlenecks, especially in areas like systems engineering, where strict compliance to protocols and safety standards is non-negotiable. Aerospace and defense projects often involve long-term commitments, and the emphasis on predictability, thorough documentation, and risk management may make certain tasks less suitable for Agile’s fast iterations. This mismatch can hinder Agile’s full benefits, leaving some aspects of the project stuck in inefficient workflows.

Without proper management and a clear strategy for balancing Agile and Waterfall practices, the hybrid approach can detract from overall project effectiveness. Employees might not fully buy into Agile’s value if they find it burdensome to integrate into a predominantly Waterfall culture, leading to resistance, diminished productivity, and failed Agile implementation. For A&D companies, moving beyond the hybrid state and fostering a culture that supports Agile methodologies will be essential to achieve seamless project management and drive innovation in complex systems development.

Tools such as Atlassian, Kanban boards, and GitLab play a critical role in facilitating Agile processes. However, the survey revealed a need for improved training programs, as many participants feel inadequately trained. The findings align with existing research, indicating the importance of tool integration and user training for effective Agile implementation (Azizyan et al., 2011).

The survey results also indicate that a segment of participants expressed resistance to Agile methodologies, reflecting a preference for traditional Waterfall practices. This resistance often stems from a comfort with the structured, sequential nature of Waterfall, which provides clear roadmaps and predictability. Individuals who prefer Waterfall methodologies typically value its thorough upfront planning and well-defined stages, which they perceive as essential for managing complex projects with stringent requirements and regulatory standards. The hybrid approach is prevalent, reflecting the need to balance Agile’s flexibility with Waterfall’s control and predictability, essential for regulatory compliance (VanderLeest & Buter, 2009).

Despite the benefits of Agile, the survey underscores the necessity for tailored approaches to fit unique project demands and organizational cultures. MBSE integration within Agile frameworks is viewed positively, enhancing requirement traceability, early validation, and stakeholder communication, despite some challenges in balancing iterative development with upfront modeling (Noguchi et al., 2020). While the integration is substantial, continued efforts are needed to address the challenges and barriers to broader adoption. Costly tool licenses are purchased, and engineers are trained on a modeling language and tool, with these engineers being designated as “modelers” on the development team. Development continues as usual, with the modelers documenting architecture and design decisions after they are made. Occasionally, the model helps identify potential issues, but it’s mostly used for recording decisions rather than as a design tool. Over time, the model’s use declines as it hinders more than it helps, leading to the conclusion that MBSE is a passing trend and not a solution for integration and quality challenges. The question arises about what defines a successful MBSE approach that can truly benefit an organization. Delligatti builds upon the INCOSE definition and highlights three core components of MBSE: a modeling language, a modeling tool, and a modeling methodology (Delligatti, 2013). Although BAE has a modeling language and tool, it lacks a defined methodology. A modeling methodology is crucial as it outlines the objectives of the modeling effort and specifies the tasks and standards to be followed in creating the model. This emphasizes that simply having a system model does not automatically translate into value for an organization, nor does it represent a genuine MBSE approach. The real value is derived from the systems engineering processes employed and the actual development of the model (Haskins, 2011). By overcoming these obstacles, the company can fully leverage the benefits of MBSE and Agile, optimizing their project management processes and improving outcomes in the complex and regulated environment (Sundaram & Brownlow, 2018).

In terms of project performance, 55.3% of participants in our study noticed improvements with MBSE in Agile projects, though the benefits varied depending on project circumstances. Literature supports these findings, showing quantitative benefits of integrating MBSE within Agile, including better estimation reliability, productivity, and lower defect rates (Huss et al., 2023). Qualitative feedback further underscores the need to address cultural and structural barriers to Agile adoption (George, 2023). Overall, our survey data align with existing literature, emphasizing the advantages of Agile methodologies and the need for continued support and training to optimize project management practices at BAE Systems. Participants discussed how Agile methodologies and MBSE have been integrated into their projects at BAE Systems to enhance development efficiency and collaboration. For example, in “Project X,” bi-weekly sprint planning, daily stand-ups, and continuous integration/continuous deployment facilitated iterative progress and rapid feedback, while MBSE ensured comprehensive requirement traceability and early validation through SysML models.

Despite initial implementation delays, significant successes included improved team collaboration and product quality. Another example highlighted the challenges of a hybrid Agile-Waterfall approach, where contracts followed Waterfall, but actual work used Atlassian tools. This hybrid approach led to delays, indicating a pure Agile framework might have expedited product acceptance. Another study by Kusters et al. (2017) examines the challenges and risks that arise when integrating Agile and traditional development methods within hybrid organizations, particularly regarding their impact on coordination and collaboration. Combining these approaches is notably difficult for many organizations due to the differing cultures and conditions inherent to each method, despite their respective strengths and benefits. Understanding these challenges is crucial for effectively managing the integration process. This study aims to identify and validate a comprehensive overview of such issues (Kusters et al., 2017).

Various projects demonstrated Agile’s effectiveness in managing requirements and adapting to evolving needs, with practices like weekly scrums and bi-weekly sprints keeping teams organized and stakeholders informed. Transitioning to Agile often required adjustments in team mindset and approach. Initial challenges were overcome by collaborative modeling and real-time feedback, fostering continuous improvement and better adaptability.

The integration of Agile and MBSE consistently led to enhanced project outcomes, despite the difficulties faced with hybrid methodologies. The survey responses underscore the benefits of fully embracing Agile practices for improved collaboration, product quality, and adaptability in project management at BAE. The hybrid methodology combining MBSE and Agile approaches in managing complex systems can be detrimental due to integration challenges, communication barriers, and resource allocation issues. The differing principles of MBSE and Agile can lead to conflicts and misalignment, while continuous communication between analysts and model developers might cause misunderstandings and delays. Balancing resources and ensuring consistent quality can be difficult, and managing stakeholder expectations can become complex. These potential drawbacks need careful management to avoid negatively impacting the project’s success (Power et al., 2021).

The objective of this paper was to identify challenges, limitations, and opportunities in the transition from Waterfall to Agile methodologies in the A&D sector from actual experiences from industry, with a focus on the role of MBSE in this transition. The survey results provide a comprehensive overview of the current state and perceptions of integrating MBSE in Agile at a prominent A&D company. The findings indicate a strong preference and positive reception towards Agile practices among industry professionals with a significant number of participants expressing favorable views. Agile methodologies are praised for their flexibility, improved efficiency, and enhanced collaboration, which align well with the dynamic needs of projects. Participants reported varying levels of experience with Agile practices, with the majority having substantial experience that contributes to an understanding of its benefits and challenges.

Those with extensive experience, such as 20 years, provide valuable insights into the long-term application and evolution of Agile methodologies. Conversely, the experiences with Waterfall practices varied widely, with some participants indicating over 40 years of experience. This diversity underscores the historical dominance of Waterfall in the company and its continued relevance, particularly for projects with well-defined requirements and stable environments. However, the rigidity and longer development cycles of Waterfall pose significant challenges in the fast-paced environment at BAE Systems, as reflected in participant feedback. The findings highlight a critical tension between traditional and emerging methodologies, emphasizing the need for adaptability and innovation in project management.

The integration of MBSE into Agile projects has been notably effective in capturing and managing requirements, with 74.36% of participants finding it very effective or effective. This highlights MBSE’s role in enhancing the precision and traceability of project requirements, thereby improving overall project outcomes. Early-stage modeling and simulation, as supported by MBSE, are particularly beneficial in facilitating iterative design and reducing rework, contributing to time-to-market improvements.

The diversity in participant experience with Agile methodologies—ranging from those with extensive experience of up to 20 years to those with varying levels of engagement—provides valuable insights into both the benefits and challenges associated with Agile adoption. The substantial experience of many participants contributes to a nuanced understanding of Agile’s impact and evolution over time. Conversely, the broad range of experience with Waterfall methodologies, some extending over 40 years, highlights the historical significance and ongoing relevance of Waterfall practices, particularly for projects characterized by well-defined requirements and stable conditions. However, the rigidity and extended development cycles of Waterfall methodologies present notable challenges in the fast-paced and adaptive environment at BAE Systems. This tension between the traditional Waterfall approach and the more dynamic Agile practices reflects a broader shift within the company towards embracing Agile principles while grappling with the limitations of established methodologies. The integration of MBSE into Agile projects has emerged as a particularly effective strategy for managing and capturing requirements.

In summary, the survey reveals a clear trend towards adopting Agile methodologies within BAE Systems, supported by the effective integration of MBSE practices. This shift reflects a broader industry movement towards more adaptive and responsive project management approaches. The findings address the importance of continued training and organizational support to maximize the benefits of Agile and MBSE, addressing the challenges of transitioning from traditional Waterfall practices. Specifically, leadership buy-in and cultural transformation are essential factors for fostering a successful transition. However, a limitation of this is often budget and further research into the financial impact and scalability of these methodologies in complex systems would be valuable. Additionally, this study focused on perceptions of employees at BAE on their teams’ transitions from Waterfall to Agile, and future research could survey additional companies to get a more diverse representation of experiences and approaches. Alternatively, while employee buy-in and perspectives are important elements to successful transitions towards Agile, an evaluation of case studies could provide valuable insight into quantifying the benefits of completely Agile, completely Waterfall, or a hybrid approach in project outcomes.

In conclusion, the purpose of this study was to explore how MBSE supports the transition from Waterfall to Agile methodologies and its impact on project management processes, efficiency, and time-to-market in the A&D sector. As companies evolve, embracing these methodologies will be crucial for maintaining competitiveness and achieving strategic objectives.

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