In today’s turbulent and complex world, organizations, especially defense organizations, face increasing challenges. Rapid environmental changes, dramatic technological advancements, and growing security threats highlight the need for adaptability and agility in these organizations more than ever. In this context, project portfolio management, as one of the most critical organizational processes, plays a vital role in achieving strategic goals and responding to these challenges. Defense organizations, due to the unique nature of their activities and missions, are constantly faced with projects of unique dimensions and complexities. These projects require flexibility, speed, and the ability to respond quickly to unexpected changes. In such circumstances, traditional project management approaches, which are often based on detailed and fixed plans, cannot meet the needs of these organizations. Therefore, the need to pay attention to new approaches to project portfolio management, especially the agile approach, is felt more than ever. The agile approach, with its emphasis on flexibility, collaboration, and responsiveness to change, can bring significant benefits to the management of defense organizations’ project portfolios. This approach, by providing frameworks designed based on continuous feedback and adaptability to changing conditions, enables more effective and efficient project management. Accordingly, implementing agile principles in defense project portfolios can lead to increased project delivery speed, reduced costs, improved quality, and increased stakeholder satisfaction. The present research, understanding the importance and necessity of implementing agility in the project portfolios of defense organizations, examines the challenges and opportunities facing these organizations in this field. The main objective of this research is to identify the key agility factors affecting defense project portfolios and to provide practical solutions for the effective implementation of these factors. In this regard, using mixed research methods and utilizing expert opinions, the factors affecting agility will be identified and prioritized, and a comprehensive framework for implementing agility in defense project portfolios will be presented.

A project portfolio consists of various components such as projects, programs, sub-portfolios, and ongoing operations. All components are grouped together to facilitate the management of work in order to effectively achieve strategic business objectives. The projects or programs within a project portfolio are not necessarily interdependent or directly related (Forozandeh & Ardalani, 2024; Nielsen, 2021; Pennypacker & Dye, 2002). In other words, it can be stated that they are typically unrelated. On the other hand, the components may share common resources or even compete for funding. The project portfolio is guided under the auspices of a specific organization. Company managers must select portfolios of projects to invest in to achieve objectives. Project portfolio selection is recognized as a periodic and continuous effort that involves selecting and funding portfolios of projects that support the stated goals and objectives of the organization. One of the important aspects of this decision-making process is considering resources and other constraints. In other words, one of the most important reasons for project portfolio selection is the fact that the accumulated budget required by all candidate projects far exceeds the available investment resources (Mohagheghi et al., 2019). According to the standard, a project portfolio is a collection of projects, programs (a set of related projects managed in a coordinated way to obtain benefits not available from managing them individually), sub-portfolios, and operations managed as a group to achieve strategic objectives more effectively (Forozandeh & Ardalani, 2024).

In the project portfolio lifecycle, all organizational needs are first identified, creating opportunities for the business and intended investments, and the best combination of projects is selected for the project portfolio from among all considered methods (Mann et al., 2023; Moran, 2015]. To carry out the projects, necessary coordination and planning must be done, and after final approval and evaluation, the impact of each project on the overall success of the organization is assessed, and the benefits of implementing each project are determined (Lewis et al., 2014). The most common continuous lifecycle of a project portfolio includes several stages: initiation, planning, execution, and optimization. The main activities of these stages are shown in Figure 1 (Forozandeh & Ardalani, 2024).

According to the statements of many authors, it can be concluded that creating a single definition of agility is very challenging. However, the concept of agility is constantly expanding with new approaches and characteristics. On the one hand, this shows that achieving a definitive and fixed definition of agility is difficult to achieve. On the other hand, the concept of agility is constantly adapting to current developments and thus remains relevant and modern. Agility refers to the ability of an organization or system to adapt quickly and effectively to changing conditions, priorities or market demands through increased flexibility, responsiveness and continuous learning. In the context of project portfolio management, agility focuses on aligning projects with organizational goals, enabling rapid decision-making and delivering value incrementally while adapting to uncertainty and change (Matharu et al., 2015).

Agile methodology encompasses a set of values, principles and practices that integrate iterative development, testing and feedback into a new approach to software development. Agile software development methodologies are considered lightweight approaches that can use an incremental and iterative life cycle, with short iterations and requirements that can be modified during development with extensive customer participation (Schiel, 2011). Agile methodologies are increasingly being adopted by companies around the world to address the increasing complexity of software and evolving user demands. Adopting agile methodologies offers several benefits, including frequent delivery, customer satisfaction, transparency, flexibility, increased productivity, improved software quality, and predictability. Agile methodology is implemented through different approaches with the appropriate methodology being selected depending on the type of project. The most commonly used agile methodologies are Extreme Programming (XP), Scrum, and Kanban. In the following sections, the most common agile methodologies in detail will be examine (Barraood et al., 2021).

According to the statements of numerous authors, it can be concluded that establishing a unified definition of agility is highly challenging. Nevertheless, the concept of agility is continually expanded by new approaches and characteristics. On the one hand, this implies that achieving a definitive and consistent definition of agility is hardly attainable. On the other hand, the concept of agility continuously adapts to ongoing developments, thereby remaining relevant and modern. Agility refers to the ability of an organization or system to rapidly and effectively adapt to changing conditions, priorities, or market demands by enhancing flexibility, responsiveness, and continuous learning. In the context of project portfolio management, agility focuses on aligning projects with organizational goals, enabling swift decision-making, and delivering value incrementally while adapting to uncertainty and change (Matharu et al., 2015).

Agile methodology encompasses a set of values, principles, and practices that integrate iterative development, testing, and feedback into a novel approach to software development. Agile software development methods are considered lightweight approaches that can leverage an incremental and iterative lifecycle, accompanied by short iterations and requirements that can be refined during development with extensive customer involvement (Schiel, 2011). Agile methods are increasingly adopted by companies worldwide to address the growing complexity of software and evolving user demands (Petit et al., 2023). The adoption of agile methods offers numerous benefits, including frequent delivery, customer satisfaction, transparency, flexibility, enhanced productivity, improved software quality, and predictability. Agile methodology is implemented through various approaches, with the choice of the appropriate method depending on the project type. The most commonly used agile methods include Extreme Programming (XP), Scrum, and Kanban. In the following sections, the most prevalent agile methods in detail will be explore (Bittner et al., 2017; Laleb et al., 2022).

Kanban is a change management method, not a framework. Kanban applies a set of managerial practices for software, derived from production systems. The term “Kanban” is Japanese, meaning “visual record” or “visual card.” Kanban describes a process for implementing change within an organization, providing sufficient detail for repeatability. The context in which this process can be applied initially focused on software maintenance, later expanding to general software development, and eventually encompassing IT operations, IT services, and other knowledge work domains. Unlike focusing on being agile, which may (and should) lead to success, Kanban emphasizes achieving success, which may result in agility at any level (Nielsen, 2021; Remta et al., 2023]. Similar to Scrum, Kanban is used for product management, with an emphasis on continuous and timely delivery. The Kanban process is designed to assist teams in working together more efficiently. Kanban is generally recognized as a time management system in manufacturing companies, aiding in decisions regarding what to produce, when, and in what quantity. Anderson developed this system and transformed it into a change management system, basing Kanban on the following principles:

Scalable agile frameworks emerged due to the successful application of agile methods in small companies and the interest of larger enterprises in achieving similar results in more complex projects. These frameworks enable the scaling of agility in large organizations and facilitate the integration of agile and lean methods to meet industry-specific needs. To scale agility in organizations, several factors must be considered: team size, geographical distribution, entrenched culture, system complexity, legacy systems, regulatory compliance, organizational distribution, degree of governance, and business focus.

Agile methods (such as Scrum, Kanban, etc.) are typically designed for small teams (5 to 10 members). However, when a large organization with dozens or hundreds of teams seeks to adopt these methods, adjustments are necessary to ensure coordination between teams, manage dependencies, and implement agile principles at a macro level. This process of expanding and adapting agile methods to a larger scale is referred to as agile scaling (Almeida & Espinheira, 2021).

Companies aim to scale agile frameworks like Scrum to a broader level to capitalize on the process improvements they may have achieved at the team level. Scaling refers to multiple agile teams working together to deliver an integrated outcome, thus being closely interdependent (Alqudah & Razali, 2016; Papadimitropoulou et al., 2023). If such dependencies do not exist, teams operate in parallel, and scaling is unnecessary. The principles of agile scaling involve working with multiple teams, necessitating agile management. Therefore, it must be ensured that the shared goal is understood by all. Additionally, team coordination must be sufficient. While self-organization and accountability are encouraged, team goals and alignment with the established vision and priorities must be maintained. Numerous challenges exist in scaling agile, which is why frameworks have been developed to regulate agility in a broader context (Mann et al., 2023).

The most prevalent scalable agile frameworks in organizations are Scaled Agile Framework (SAFe), Large-Scale Scrum (LeSS), Disciplined Agile Delivery (DAD), and Spotify Models. The foundation of all scalable agile frameworks is the practice of agile methods, particularly Scrum (Larman & Vodde, 2016; Alqudah & Razali, 2016).

SAFe is defined by its creators as a knowledge base of integrated, proven principles, practices, and guidance that brings the power of agility to those building the world’s most critical systems. SAFe provides prescriptive guidelines for implementing agile development at an enterprise scale in large organizations. Its first version was released in 2011. SAFe is a scalable and configurable framework that helps organizations deliver new products, services, and solutions in the shortest sustainable lead time. It is a system that guides the roles, responsibilities, and activities necessary to achieve sustainable and competitive technological advantages. The SAFe approach encompasses an extensive list of artifacts and deliverables (Almeida & Espinheira, 2021; Larman & Vodde, 2016; Project Management Institute, 2017). SAFe is composed of seven core competencies, each representing a set of related knowledge, skills, and behaviors that collectively enable companies to achieve business agility. These competencies include Agile Leadership, Team and Technical Agility, Agile Product Delivery, Enterprise Solution Delivery, Portfolio Management, Organizational Agility, and Continuous Learning Culture (Grundler & Westner, 2019). The SAFe scaled agile framework highlights four organizational levels: Team, Program, Value Stream, and Portfolio. Each level has its specific activities, and all levels are interconnected. SAFe specifically defines the standard Scrum team size, consisting of five team members. A program includes five to twelve agile teams, or 50 to 125 individuals, dedicated to the program and capable of delivering capabilities or business value. The Value Stream level ensures that multiple teams remain aligned. At the Portfolio level, teams focus on new ideas (Moran, 2015). Benefits of SAFe include improved collaboration and dependency management among agile teams and increased transparency within the organization.

Large-Scale Scrum (LeSS) is applied to numerous teams working together on a single product. LeSS specifies organizational changes and mandates the creation of cross-functional teams by eliminating traditional roles (such as project manager or team lead). It has been reported that the use of agile methods enables the development of cross-functional teams, where a combination of technical and functional skills is observed. The primary goal is to always be highly objective, simple, and transparent. Additionally, the framework focuses on the whole product, customer centricity, continuous improvement, lean thinking, and other aspects. In LeSS, all sprints end simultaneously, and all Scrum teams work on a single product backlog. LeSS is recommended for up to eight teams with eight members each. For larger teams, LeSS Huge is available. Conceptually, LeSS Huge can be viewed as adopting LeSS in an environment with multiple LeSS structures layered on top of each other (Aghajani et al., 2023; Schwarzgruber et al., 2021). An organization implementing LeSS must be organized around its products in a lightweight manner. Individual teams are led by a Product Owner at a hierarchical level with the Product Owner.

The Disciplined Agile Delivery (DAD) approach was introduced as a solution for delivering IT solutions at the 2019 International Conferences on Internet Technologies and Internet Society and is defined as a dynamic, learning-oriented, hybrid, and agile approach for Internet-related international conferences. DAD focuses on providing a flexible and context-tailored approach throughout the entire process. The high-level DAD lifecycle includes five phases from initial concept to production: Inception, Initiation, Construction, Transition, and Production. In the delivery phases, DAD supports four sub-cycles: Agile/Basic (based on Scrum), Lean/Advanced (based on Kanban), Exploratory (based on Lean Startup), and Continuous Delivery. Teams can select the appropriate sub-cycle based on their conditions. DAD considers aspects such as analysis, design, architecture, programming, and testing as context-dependent and does not prescribe a uniform lifecycle for all projects. DAD provides three main process domains with various options (referred to as process blades) for each goal. These blades are defined as interrelated components within the organization, where a change in one may impact the others. DAD specifies decision points with a list of options and potential starting points (Kock et al., 2020; Grundler & Westner, 2019).

Masoud Aghajani conducted a study titled Success Factors of Agile Project Portfolio in Large Organizations. This study explores the concept of success and its influential factors in sets of large organizations’ agile information technology and software development projects. Using a multiple case study approach, they analyzed the agile project portfolios of seven large organizations and identified four success criteria and 15 success factors, categorizing them into a unique agile project portfolio success framework. Figure 2 illustrates the model derived from the corresponding article.

Sabrina Schwarzgruber conducted a study titled Requirements for Agile Project Portfolio Management for Diverse Companies. In this study, project portfolio management is employed to effectively utilize available IT resources in order to increase the participation of IT projects in the company’s overall strategy. Agile project portfolio management enables organizations to respond flexibly in a changing environment. In this paper, the framework of our research project outline —which adopts a design science approach—and present the results from the first iteration of the study. By conducting a case study in a company in the energy industry, an artifact was created. Figure 3 presents a model of the requirements for agile project portfolio management for diverse companies.

Vasco Frankira Dias conducted a study titled An Agile Portfolio Management Model for Insurance. In this study, considering the limited scientific knowledge in combining agility with project portfolio management—especially in the insurance industry—a new agile project portfolio management model for insurers was designed and tested. This model demonstrates how international agile and project portfolio methodologies can be adapted to the current practical approaches in the insurance industry. The results indicated a high level of satisfaction with the model’s implementation, showing that the proposed model can enhance strategic alignment, increase the organization’s strategic focus, improve lateral alignment and visibility, and support the coordination of organizational capacity.

The above overview indicates that the general models for agility in project portfolios are very limited. Therefore, to better implement agile models in project portfolios, it appears necessary to introduce more generalized models derived from a broad range of diverse factors. Moreover, the use of agile methods as powerful tools in the project portfolio domain has not received much attention so far. Accordingly, the aim of this study is to develop a comprehensive and accurate model for implementing agility in project portfolios. In this context, a model inspired by one of the reputable articles—as shown in Figure 4, has been considered as a starting point for this journey. This model, by schematically outlining the factors, requirements, and fundamental interconnections, provides an initial framework for implementing agility in project portfolios and clearly delineates the objectives of this approach. In this research, with the goal of advancing agile project portfolio implementation, a novel step has been taken. To achieve this goal, an extensive set of agile factors has initially been collected from reputable sources. After gathering these factors, they were categorized and analyzed within the various stages of the project portfolio life cycle. To develop a more precise model in this study, the fuzzy Delphi method and ISM (Interpretive Structural Modeling) will be utilized. This model, by illustrating the hierarchy and mutual influences of the factors, offers a comprehensive and deeper insight into the challenges and opportunities of implementing agility in project portfolios. Finally, the most important agile execution methods for project portfolios will be introduced, and as the primary outcome of this research, appropriate agile methods and solutions will be proposed for each of these factors.

A questionnaire serves as a fundamental research tool in scientific studies, consisting of a series of questions designed to gather information from respondents. This method is relatively inexpensive, quick, and efficient, allowing researchers to obtain substantial amounts of data from a large sample of the target population. Questionnaires are commonly utilized in various research designs, particularly in surveys, and are effective for measuring behaviors, attitudes, opinions, and objectives of a relatively large group in a cost-effective and timely manner.

The Delphi method, introduced by Dalkey and Helmer in 1963, is a survey-based approach that relies on expert opinions and possesses three main characteristics: anonymous responses, iteration with controlled feedback, and statistical group responses. This systematic method collects and coordinates informed judgments from a group of experts on a specific question or topic. In many real-world scenarios, expert judgments are not easily expressed or interpreted as definitive quantitative numbers. Consequently, precise data and numbers often fall short in modeling real-world systems due to the ambiguity and uncertainty inherent in decision-makers’ judgments. To address this challenge, the theory of fuzzy sets, proposed by Lotfi Zadeh, offers an appropriate tool for managing ambiguity and uncertainty in the decision-making process. Therefore, in this study, the Fuzzy Delphi method was employed to validate and screen the identified indicators.

Interpretive Structural Modeling (ISM), introduced by Sage in 1977, focuses on classifying factors and identifying relationships between criteria. The ISM approach is an effective methodology for addressing issues where qualitative variables, which have varying levels of importance, exert mutual impacts. This technique allows for the identification of relationships and dependencies among qualitative variables related to the problem at hand. The steps required to develop the intended model using the ISM technique are outlined below (Papadimitropoulou et al., 2023). In this step, experts perform pairwise comparisons of the criteria, responding to these comparisons based on a specified scale.

By converting the symbols of the SSIM matrix into binary values (0 and 1) based on the following rules, the initial reachability matrix is obtained:

The initial reachability matrix must be checked for transitivity, meaning if \(i,j=1\) and \(j,k=1\), then \(i,k=1\). In other words, if criterion A is related to criterion B, and criterion B is related to criterion C, then criterion A must also be related to criterion C.

In next step, the input (prerequisite) and output (reachability) set for each criterion are calculated, and the common factors are identified. A criterion is considered to have the highest level if its output (reachability) set is equal to its common set. After identifying this variable or variables, their corresponding rows and columns are removed from the table, and the process is repeated for the remaining criteria. In final step, based on the levels of the criteria and their interrelationships, the interaction network is drawn.

The MICMAC analysis is based on the driving power (influence) and dependence (impact) of each variable, providing further insight into the scope of each variable. In this analysis, variables are categorized into four groups: autonomous, dependent, linkage, and independent.

In the examination and analysis of the dimensions of agility in project portfolios, various aspects were explored, and influential factors were evaluated, leading to the final stage of the study. In this phase, the factors identified as key components through the Fuzzy Delphi method and were meticulously prioritized using a TOPSIS-based approach. For each agility factor, scores and associated weights were calculated and analyzed to reflect their actual impact on the success of the project portfolio.

The results of this analysis are illustrated in Table 3, which is presented within the framework of the project portfolio lifecycle. This table provides valuable conclusions regarding project portfolio agility and serves as a guide for decision-makers and project managers seeking to enhance processes and improve the quality of project portfolio management.

Through this approach, the importance of each factor contributing to project portfolio agility was clarified, and a systematic foundation was established to facilitate significant improvements and developments in project management practices. These findings are anticipated to serve as a robust basis for strategic decision-making in this domain, ultimately leading to increased productivity and enhanced stakeholder satisfaction.

In this section, the ISM method is used to determine an interpretive structural model of the factors affecting agile implementation in the project portfolio. These factors are 22 and are introduced in Table 4.

In the first step, the structural self-interaction matrix of the research formed using the respondents’ opinions. To form the structural self-interaction matrix, experts consider the criteria in pairs and respond to the pairwise comparisons based on the following spectrum.

The self-interaction matrix is given in Table 5.

The Driving Power of agile in PPM implementations is deduced as the sum of ith row. The Dependence of agile in PPM implementations is deduced as the sum of jth column. This is as displayed in Table 6. The Final Reachability Matrix then undergoes repetitive iterations to achieve Level Partitioning of the agile in PPM Implementations. It was achieved in eight iterations, thus partitioning the agile at nine levels and showcasing their hierarchical dependence. This is depicted below in Table 7.

In the fifth step, using the levels obtained from the criteria, the ISM interaction network is drawn. If there is a relationship between two variables i and j, it is shown by a directional arrow. The final diagram created by eliminating the extraneous states and also using the level segmentation is shown in Figure 5.

According to Figure 5, the research model consists of 9 levels. The ninth level, which includes the criterion of planning in line with the ongoing needs of customers and stakeholders, is the most influential criterion that directly affects the two criteria in the eighth level, namely planning for rapid response to changes including demand/strategy technologies and flexibility. This influence continues in a hierarchical manner from bottom to top, so that the criteria in the first level are the most influential criteria. The variables of planning for rapid response to changes including demand/strategy technologies and flexibility are in the second level, which lead to the definition of short-term projects by considering the limitations and scope of each, reducing the risks of the project portfolio. This process up to the middle level includes the design of components and the agile project portfolio management process and the independence of the teams involved in the process in terms of authority. Then a set of intermediate variables continues such as clarity of roles of key elements of the project portfolio, establishment of continuous control and monitoring cycles, continuous improvement of project portfolio processes. At the upper levels, are located the variables of defining short-term projects considering the limitations and scope of each, increasing customer satisfaction and responsiveness, and integrating, optimizing and balancing project portfolio components. Finally, the variables of continuous learning and lessons learned and modifying and updating capabilities and capacities according to agility are located at the highest level, which represent the output variables.

The research model can also be shown in terms of influence and dependency as shown in Figure 6. Interpretive structural modeling diagram is an analytical method used to identify the relationships between different elements of a complex system. The main purpose of this method is to analyze and organize the connections between elements based on their influence and dependency. Accordingly, the criteria for reducing project portfolio risks, senior management support and participation, rapid response planning to changes including demand/strategy technologies and regular planning with the ongoing needs of customers and stakeholders are independent variables. These variables have low dependence and high guidance, in other words, high impact and low impact are the characteristics of this variable. The criteria for planning based on real-time components of the portfolio and continuous learning and lessons learned are dependent. These variables have strong dependence and weak guidance. These variables basically have high impact and little impact on the system. The remaining criteria are interface type. These variables have high dependence and high guidance power, in other words, the impact and impact of these criteria are very high and any small change in these variables causes fundamental changes in the system.

This research demonstrates that defense organizations, including the aerospace industry, must pay special attention to the project portfolio lifecycle to achieve agility in their project portfolios. Each stage of this lifecycle (initiation, planning, execution and monitoring, delivery, and optimization) should be approached with an agile and flexible mindset.

Based on the Interpretive Structural Modeling (ISM), aerospace organizations must pay special attention to the hierarchy of factors when implementing agility in their project portfolios. According to Figure ۵, planning aligned with the ongoing needs of customers and stakeholders is identified as the most fundamental factor. This factor, like the roots of a strong tree, influences other factors and is not directly affected by any other factor. This means that any change or lack of attention to customer and stakeholder needs can have a profound impact on the entire system. Therefore, focusing on this factor and striving for a precise and continuous understanding of their needs is the key to successfully implementing agility.

Factors such as rapid response planning to changes (including demand and strategic technologies) and flexibility play an intermediary role. These factors transfer the influence of foundational factors to outcome-oriented factors, acting as levers that can either strengthen or weaken this influence. These intermediary factors reflect the organization’s ability to adapt to environmental changes and evolving needs.

Factors such as maximizing the value of the project portfolio, transparency in the roles of key portfolio elements, increasing customer satisfaction and responsiveness, and team autonomy in decision-making are positioned at a higher level. These factors represent the outcomes and outputs of the agility process. Achieving these results indicates the organization’s success in implementing agility principles and delivering value to stakeholders. Finally, factors such as continuous learning and capturing lessons learned, as well as revising and updating capabilities and capacities in line with agility, are recognized as the highest-level outcomes and achievements. These factors reflect the cycle of continuous improvement and dynamism at the core of the agile approach. An organization that continuously learns, improves itself, and enhances its capacities can achieve sustainable success in the dynamic and competitive aerospace industry.

Implementing agility in project portfolios in the aerospace industry requires a multifaceted approach that addresses each of the identified factors. Below are suitable solutions to assist aerospace industry managers in enhancing agility in their project portfolios: