Introduction
In today’s security environments, peacekeeping and stabilization operations are important instruments for the mitigation of conflicts and the support of long-term peace. Within the European Union, these operations are often framed within the so-called Petersberg tasks as an integral part of the Common Security and Defence Policy (CSDP) (Kmec, 2022; Mattelaer, 2013; Sabatino et al., 2023). These tasks are carried out by military and civilian services and include joint disarmament operations, humanitarian tasks, military advice and assistance, conflict prevention and peacekeeping, crisis management tasks involving combat forces, including peace-making and post-conflict stabilization (EU, 2020a). All these activities may also contribute to countering threats such as terrorism. Moreover, as seen after Russia’s full-scale invasion of Ukraine in 2022, the importance of stabilization operations has been renewed given the need to counter hybrid threats and sources of instability in Europe and its neighboring areas (Adriani 2023; European Union, 2022).
To cope with the complexities of these operations, interoperability is a constant requirement. Interoperability, at its best, can foster collaboration across CSDP services and smooth interactions with other players and cultures while implementing shared goals and mandates (Adriani, 2023; Zartsdahl, 2018; Kmec, 2022). As argued in studies sponsored by the European Security and Defence College, interoperability must become a “commitment”, essential “for acting together as military technicians but also as crisis manager with their civilian counterparts” (Paile-Calvo, 2016, p. 6).
The term interoperability, as examined in academic and military discourses (Nisser, 2022, p. 401), has been commonly used in reference to joint operations, particularly when discussing matters related to combining forces from different services or nationalities (e.g., Verweijen, 2017; Lockyer, 2012; Deni, 2014). Yet, often treated in managerial or technical terms, scholarly debates in the field of peacebuilding and conflict management have rarely explored interoperability as a catalyst for relationship-building, a key component of “positive peace” – peace as an active and continuing phenomenon (Shields & Rissler, 2015). Interoperability and its human factors, as argued in recent studies (e.g., Ferreyra, 2025), can also be understood as a context for building positive relationships, including attitudes, structures, and institutions that support relationships well beyond the mere absence of war.
A growing body of research emphasizes the human and cultural dimensions of interoperability, examining the skills, perceptions, and knowledge that facilitate effective cooperation in complex interagency and conflicting contexts (Paget, 2016; Rosson, 2022; Missildine & Clift, 2019; Jared, 2009; Mattingsdal et al., 2023). Concepts such as “cognitive interoperability,” “interoperability of the mind”, and “perceptive interoperability” have been used to describe socio-cultural and cognitive capacities necessary for collaboration in U.S. and NATO operations (Rosson, 2022; Paget, 2016). Earlier work by RAND researchers also proposed useful frameworks for classifying JIIM (joint, interagency, intergovernmental, and multinational) competencies for military officers at strategic, operational, and tactical levels (Markel et al., 2011). Moreover, Moelker, Soeters, and vom Hagen (2007) advanced intercultural perspectives, identifying, for example, the role of sympathy as the “cement” of effective interoperability.
In general, it is known that officers need to be mentally prepared for interaction in remote locations; they should possess adaptability, critical thinking skills, an understanding of different professional domains, the ability to maintain a team focus, and training in cognitive, affective, and metacognitive domains (e.g., Fürst & Kümmel, 2012; UN, 2012). In a recent study, I aimed to identify and clarify knowledge requirements for interoperability at strategic, operational, and tactical levels of analysis. I started investigating U.S. and UN peacekeeping and stabilization experiences with this objective in mind. Notably, during research visits in 2023, I established formal contacts with relevant U.S training institutions and conducted in-person and remote interviews with experienced military officers. I applied a pragmatic deductive framework based on Lundvall’s taxonomy of knowledge to this empirical material, distinguishing four categories of knowledge: know-what, know-why, know-how, and know-who (Lundvall & Johnson, 1994).
In this study, I found both support for every one of Lundvall’s categories and that their relevance and applications may vary across strategic, operational, and tactical levels (Ferreyra, 2025). The study elucidated how knowledge categories manifest in specific contexts at various organizational levels in peacekeeping and stabilization operations. These findings offered valuable empirically grounded insights into the forms of knowledge that underpin effective interoperability and provided useful analytical points of reference for examining other organizational contexts (Ferreyra, 2025).
This line of inquiry, however, has not yet been extended to the European context. Within the CSDP framework, the taxonomy of knowledge that underpins effective interoperability in EU peace operations remains insufficiently explored and theorized in the literature. Because of this, I continue this line of inquiry, applying a similar framework and focusing now on EU peace operations.
The principal research question guiding this exploratory study is “What types of knowledge are required of European military officers for the development of effective interoperability in the context of EU peace operations, and how do these forms of knowledge compare with those observed in other organizational and geopolitical contexts?”
The article seeks to stimulate theoretical development and future research by grounding the analysis in the philosophy of classical pragmatism (Dewey, 1938; Addams, 2007), while also drawing on comparative insights from previous research on U.S. stability operations (Ferreyra, 2025). Pragmatism’s emphasis on context, problem-solving, and the rejection of rigid dualisms, and particularly, Jane Addams’ principles of peaceweaving provide a useful approach for addressing various complexities of relationship-building and interoperability.
The study combines deductive and inductive methods. The deductive component is based on a pragmatic analytical framework that uses Lundvall’s knowledge categories and corresponding working hypotheses (Lundvall, 2006; Lundvall & Johnson, 1994). The inductive inquiry draws on primary documentary sources related to EU military operations, including EU institutional documents, such as documents from military training programs, course curricula, qualification frameworks of the European Security and Defence College (ESDC), and CSDP documents. Secondary academic literature (articles, books, and research papers) is used to contextualize and support the analysis.
The following section presents the pragmatist approach drawn on in this article; after this, the analytical framework is described with an introduction of Lundvall’s taxonomy of knowledge forms and a levels-of-analysis framework (strategic, operational, and tactical) applied to the CSDP context. After this is a section describing the methodology and data material used; after that, a section presenting the results of the EU peace operations study. The article concludes with a series of final considerations, a synthesis of the findings, and practical recommendations.
Interoperability from a Pragmatist Perspective
Peacekeeping and stability operations often take place in complex collaborative environments. As various studies have shown, an increased need for cooperation and coordination tends to complicate interactions; mandates can become harder to meet and operations can be exposed to greater risks (Sabatino et al., 2023; Soeters, 2018, 2020; Zartsdahl, 2018; Ruffa & Rietjens, 2023; Ferreyra & Soeters, 2024). The philosophy of pragmatism, with its focus on practical consequences and experiential learning (Dewey, 1938; Addams, 1907/2007; Shields, 2003), provides a useful lens for understanding interoperability as a dynamic context of inquiry, learning and resolution within organizations rather than as an end-state.
The pragmatist perspective helps in the understanding of interoperability as a domain of practical problems arising from experience and shaped by culture (Dewey, 1938). It is a setting in which the facts, ideas, perceptions, lessons and techniques attained through inquiry can be tested in action as people work to resolve diverse practical problems. And, as interoperability practices inherently connect actors and groups, inquiry can go beyond individual practitioners to form a “community of inquiry” (Dewey, 1938), bringing together varied experiences and mindsets to articulate shared problems and courses of action.
In peace operations, interoperability has a further pragmatic or practical function: the construction of fluid, positive relationships aimed at transforming conflicting situations into “peace”. This approach converges with Jane Addams’s pragmatist ideas (Addams, 2007) and their reinterpretation through the concept of peaceweaving (Shields & Soeters, 2017). Peaceweaving, the process through which positive peace is instituted, emphasizes relationship-building as an active, collaborative process in conflicting contexts while engaging people with sympathetic knowledge – a form of knowledge that develops within the community of inquiry, in which members can learn to work with others and remain open to alternative perspectives (Shields & Soeters, 2017).
There is evidence that sympathetic knowledge and understanding facilitates relationship-building and improves the effectiveness of interoperability (Ferreyra, 2025, p. 16). Rigid mindsets hinder cognitive and perceptive interoperability; by contrast, sympathetic understanding supports the development of “interoperable mindsets” and the capacity to see situations from another’s point of view within peaceweaving dynamics.
Sympathetic understanding may emerge in interactions often referred to as horizontal interoperability (Rubinstein et al., 2008) among military contingents, civilian and organizational cultures as they learn about their roles and attitudes. However, it also can manifest between mission personnel and local populations, where learning and adaptation may occur in both directions. These interactions are often termed vertical interoperability (Piché, 2018). Third, sympathetic understanding may also emerge in interactions between mission troops and host-country forces; here it has been described as diagonal interoperability (Verweijen, 2017).
Such relationships combine core competencies from the so-called Athens and Sparta models, as understood by European scholars (Kirkels et al., 2003). The Athens model envisions military “leader-mediators” who are able to deal with the social, cultural, and political complexities serving to discourage cooperation. Following Shields (2003, p. 526), the mediator role involves facilitating connections and understanding between different points of view or different experiential references. Nevertheless, in the violent environments of peace operations, peaceweaving skills must be complemented by “Spartan” competencies: the performance of core combat skills on the part of officers, who are, first of all, soldiers, in efforts to counter violence.
These (seemingly) contradictory requirements illustrate the kind of “ambidextrous” skills and knowledge that officers need to navigate diverse challenges while interoperating with joint forces and civilian organizations (Soeters, 2018). To understand how different forms of knowledge interact and fragment the knowledge base of interoperability in these operations, Lundvall’s taxonomy provides a useful and practical framework.
Lundvall’s Knowledge Taxonomy
Bengt-Åke Lundvall proposes a flexible framework of categories in knowledge management studies that helps explain and communicate how knowledge is applied in organizations (Lundvall, 2006; Lundvall & Johnson, 1994). It is based on the four categories know-what, know-why, know-who, and know-how.
“Know-what” denotes factual knowledge – information that can be articulated, broken down into data, and shared between actors. This form of knowledge can be acquired through action and through interactions between those who produce and those who use information.
“Know-why” describes knowledge of causal relationships, underlying principles, and mechanisms that shape phenomena in nature, society and human behavior. Knowledge of this kind enables actors to evaluate cause-and-effect relationships, helping to reduce errors and make sense of why things work as they do. It is often developed through reading, attending lectures, experimentation, and engagement with scientific or technical databases.
“Know-how” denotes the ability to apply techniques and skills. It is a kind of expertise in action. It may be applied to carry out tasks and missions in different situations.
“Know-who” designates an awareness of others’ abilities; knowledge of who knows what and who knows how. It includes a facility to form networks of relationships and connections with other specialists and to draw effectively on others’ expertise.
These categories often overlap with distinctions such as explicit knowledge, which can be shared through words, documents, or images, and tacit knowledge, which is experiential and harder to formalize (Polanyi, 2009). Following Lundvall (2006), the four categories can interconnect and complement in meaningful ways in communities of inquiry. For example, in military contexts, know-what may include information about a host society – such as demographics, geography, or language – while know-how refers to the skills required to interact effectively in that environment (Schmidtchen, 2007).
Lundvall (2006) also notes that education and training systems help generalize and embed knowledge in people, allowing the knowledge to be applied across different contexts. However, knowledge often takes context-specific formats and remains intertwined with its societal or organizational environments. For example, the EU Strategic Compass (European Union, 2022) provides a practical perspective on action (know-how) in response to particular challenges and problems in the European strategic context, indicating what needs to be done and what is appropriate in this context.
Knowledge related to interoperability is also likely to vary significantly across strategic, operational, and tactical levels in EU operations and missions. Interoperability activities can take many forms, appearing both in strategic planning at higher CSDP levels and in the interactions of boots-on-the-ground officers and host nationals (Paile-Calvo, 2016; Arjona, 2022). Accordingly, this study explores how knowledge and abilities can differ across these organizational levels.
Strategic, Operational, and Tactical Levels
The strategic, operational, and tactical levels of analysis, as commonly used in military and interoperability studies (e.g., Lockyer, 2012; Deni, 2014; Markel et al., 2011; Soeters, 2020; Rubinstein et al., 2008; Nisser, 2022; Larson et al., 2003), often have blurred boundaries and do not necessarily coincide with command levels. In practice, organizations such as NATO, UN or the EU may have different understandings and applications of these levels (Lawrence, 2022). Key challenges and problems, meanwhile, can arise as the focus and scope of interoperability tend to differ across the three levels.
This distinction becomes evident within the CSDP framework, where the strategic level formally includes relationships at EU headquarters in Brussels and overlaps with Operation Headquarters (OHQ) level (European External Action Service, 2019). Following Lockyer (2012) and Deni (2014), who broadly define interoperability at the strategic level as the harmonization of worldviews, strategic interests and values, this perspective can be applied to the EU member states. Key challenges thus include aligning strategic values and diverging interests (e.g., Mattelaer, 2010; Sabatino et al., 2023). For instance, Mattelaer (2008) analyzed how diverging political priorities in the EUFOR Tchad/RCA operation constrained military planning, resource allocation, and force generation processes.
At the operational level, interoperability is often described as the capacity to combine systems, forces, and planning across services (Nisser, 2022). In practice, this is where horizontal interoperability challenges become visible in mission headquarters, exercises and operations. Within the CSDP framework, for example, Sabatino and colleagues (2023, p. 104) examined how EUFOR’s Operation Althea faced difficulties in joint operational planning and in implementing operational plans owing to national caveats and differing understandings of operational attributions (see also Soeters, 2020; Ruffa & Rietjens, 2023).
At the tactical level, the focus is on executing tactics, techniques, and procedures (Deni, 2014; Larson et al., 2003). Interoperability issues often arise when forces operate with differing equipment, communication systems, or levels of capability. Challenges during deployments can also relate to vertical interoperability concerning local perceptions, distrust or misunderstanding of tasks and operations (e.g., IECEU, 2017, p. 82).
These levels and their problems often overlap, but each requires expertise tailored to its functions and problems. For instance, following Markel and colleagues (2011, p. 33), the nature and degree of understanding necessary at each level can vary significantly. At the strategic level, it is crucial to comprehend the broader strategic issues in international politics and the workings of international organizations to establish priorities with strategic partners. In contrast, at the operational and tactical levels, officers need a narrower and more intuitive understanding of joint and service capabilities (Markel et al., 2011, p. 96). Tactical commanders may often, however, base their responses and interactions more on immediate physical stimuli such as sight, sound, and body language, where operational staff officers, focused on operational art, often depend on reports and analyses for real-time coordination (Markel et al., 2011); this leads to distinctly different approaches to relationships, problems and feedback processes.
Method
The research employs qualitative methods, combining both deductive and inductive approaches. The deductive component is structured around an a priori framework based on Lundvall’s taxonomy of knowledge, with a corresponding working hypothesis and sub-hypotheses. The inductive component draws on a case study of EU peace operations –focusing on executive military operations under the Common Security and Defence Policy (CSDP) –and examines themes and patterns in how knowledge is applied across different levels of interoperability, through qualitative analysis of EU institutional and training documents.
The working hypothesis is that the relevance of the types of knowledge required for effective interoperability varies across strategic, operational and tactical levels of analysis. It proposes that the four categories of knowledge are incorporated differently at each echelon. To examine and compare relevant examples, the Lundvallian categories form the basis for four sub-hypotheses:
Effective interoperability in practice incorporates know-what knowledge.
Effective interoperability in practice incorporates know-how knowledge.
Effective interoperability in practice incorporates know-why knowledge.
Effective interoperability in practice incorporates know-who knowledge.
This deductive framework was first developed in the context of research conducted at Texas State University, and was first applied to case studies involving the United States and Brazil (e.g., Ferreyra, 2025); in this article, however, inductive inquiry and new data collection are extended to executive military operations of the Common Security and Defence Policy (CSDP). Although the primary focus of this study is the CSDP, it also draws selectively on findings and comparative insights from the U.S. case.
Regarding the CSDP framework, I accessed pertinent EU documentary sources, including primary data from numerous military training programs and course curricula published by the European Security and Defence College and CSDP operations documents and reports from the European External Action Service; I also incorporated secondary sources from research papers, articles, and books. The analysis rigorously examined key data on professional competencies and learning areas deemed essential for CSDP operations.
In this way, I identified levels of interoperability in CSDP operations and relevant data across its three levels of command and control (C2) structure (European External Action Service, 2019). These EU agencies use the C2 distinctions – strategic, operational, and tactical levels – to describe different functions and competencies required of all staff recruited for CSDP operations (ESDC, 2021; European External Action Service, 2021).
Table 1 aligns some examples of military functions and positions. As these levels often overlap, some functions may operate across multiple levels (the EU Mission Force Commander, for example). As of 2025, the Director of the Military Planning and Conduct Capability (MPCC), double-hatted with the Director of the EU Military Staff, heads the permanent command structure for non-executive military missions – EU training missions in Mozambique or Somalia, for example (European External Action Service, 2025; see also Reykers & Adriaensen, 2023). The MPCC is currently evolving to conduct small-scale executive operations as part of the EU’s Rapid Deployment Capacity ambition. For executive military operations, which allow the use of force, operation headquarters is usually provided by a Member State acting as a framework nation (European External Action Service, 2025).
Table 1
Military Positions at Different Levels of Planning/Execution for Standard EU Military Operations.
| CSDP MILITARY OPERATIONS SYSTEM |
|---|
| Strategic level |
| Chairman of the EU Military Committee (CEUMC) |
| EU Military Staff (EUMS) |
| Director of the MPCC (double-hatted as Director General of the EUMS) |
| Operation Commander (OpCdr) |
| Operation Headquarters (OHQ) |
| Operational level |
| EU Force Commander |
| Mission Force Commander (MFCdr) |
| Force Headquarters (FHQ) officers |
| Tactical level |
| Mission Force Commander (MFCdr) |
| Component Commanders (CC) |
| Sub-units |
| Special components |
[i] Note. Prepared by the author based on European External Action Service (2019, pp. 6–22; 2025).
To test the sub-hypotheses in this study, I conducted a systematic analysis and coded the collected information within Lundvall’s taxonomy to observe how the categories of knowledge manifested practically across different levels of interoperability. The inductive analysis revealed consistent themes regarding core competencies and recurring barriers at each level of interoperability.
Lundvall’s Categories in EU Peace Operations
While the EU is today a global security provider, member states have evolved as a regionalized community of inquiry, in which peaceweaving dynamics through CSDP operations tend to manifest more selectively in neighboring regions or areas that more directly threaten EU societies (Tardy, 2019). As of 2025, the CSDP conducts 21 missions and operations, most deployed in Africa and Eastern Europe, comprising military operations, civilian missions, and one civilian-military initiative. Among these, four are currently military operations with executive mandates allowing the use of force (European External Action Service, 2025). This section examines how the four knowledge forms manifest across strategic, operational, and tactical levels in EU peace operations. Table 2 provides an overview of key examples in the CSDP framework.
Table 2
Types of Knowledge and Examples at Multiple Levels of Interoperability in EU Military Operations.
| CATEGORY | EXAMPLES |
|---|---|
| Strategic level | |
| Know-What | Strategic documents (EU Global Strategy, Council conclusions), policy briefs |
| Know-Why | EU values on security and multilateralism, integrated approach principles |
| Know-How | Strategic planning; strategic thinking; political-military coordination |
| Know-Who | Key institutional actors and experts in EU services and agencies. |
| Operational level | |
| Know-What | Operational plan, shared situational awareness reports, intelligence documents |
| Know-Why | Peacebuilding theory, effects of culture and technology on interoperability |
| Know-How | Coordination and communication skills for joint/multinational operations |
| Know-Who | Understanding service-specific capabilities and leveraging their expertise |
| Tactical level | |
| Know-What | Mission planning data (terms, graphics); Recognized Maritime Picture |
| Know-Why | Behaviors facilitating secure local relationships (gender, cultural awareness) |
| Know-How | Teamwork; intercultural interaction; empathic/active listening |
| Know-Who | Building trust with local actors and leveraging their knowledge in tasks |
[i] Note. Prepared by the author.
Strategic Level
At the formal strategic level of CSDP operations, officers define and implement EU policy across both political-strategic and military-strategic dimensions (European External Action Service, 2019). The political-strategic level includes the Council, the Political and Security Committee (PSC), the EU Military Committee, and the EU Military Staff. Command and control at the military-strategic level operate externally through two mechanisms: first, by drawing on NATO planning assets under the EU–NATO Berlin Plus agreement, and second, by using national headquarters made available for EU autonomous operations (located in France, Germany, Greece, Italy, and Spain) (Lawrence, 2022, p. 6; Arjona, 2022).
Strategic Know-What
EU official and training documents suggest that interoperability at strategic levels should be supported by continuous and iterative processes of data collection involving officers serving at the EU strategic level such as the EU Military Staff and dedicated Operation Commanders (e.g., EU, 2020b; ESDC, 2021, 2024a). This is exemplified by the use of the Watchkeeping Capability (WKC), a 24-hour contact point that facilitates systematic information-sharing across all ongoing operations and missions (EU, 2020b; Lawrence, 2022). Following EU strategic-level training materials, know-what enables officers to conduct early warning and situation assessments and to evaluate options for strategic planning in intergovernmental, interagency, and multinational contexts (ESDC, 2021, pp. 15–21, 2024a, 2023).
When taking other geopolitical contexts into consideration, however, the CSDP has been operating in a particularly contested informational environment. Since Russia’s full-scale invasion of Ukraine, experts have noted an increase in foreign information manipulation and interference (FIMI), which has heightened challenges in securing credible information-sharing between EU nations and third partners (Fridman et al., 2023; European Union, 2022). In response, the EU established platforms like the FIMI Information Sharing and Analysis Centre to provide civilian and military actors with reliable data on root causes, incidents, and threats, thereby bolstering situational awareness and interoperability (European Union, 2022). The CSDP Senior Strategic Course curriculum also highlights the need for advisors to absorb information about EU institutions and decision-making processes – including the Council, Commission, Parliament, the European External Action Service, and international organizations (ESDC, 2021, 2022, 2024b). Overall, these know-what forms enhance interoperability and support the EU “integrated approach” among services, humanitarian efforts, and diplomatic initiatives (Adriani 2023; Arjona, 2022).
Strategic Know-Why
The CSDP encompasses 27 member states, each with diverse perspectives on the ambition and strategic priorities of a common defense policy (Palm & Crum, 2019; Arjona, 2022). These differences have often led to disagreements and protracted decision-making, limiting the scale and number of CSDP operations and resources, and hindering strategic interoperability (Barbieux, 2023; Reykers & Adriaensen, 2023; Mattelaer, 2013). However, as already observed in the U.S. context (Ferreyra, 2025, p. 16), acquiring strategic forms of know-why or knowledge of causal relationships can mitigate these divergences by helping decision-makers develop common interpretative frameworks to evaluate decisions and priorities in peaceweaving dynamics. In the CSDP context, these frameworks typically focus on the challenges, purposes, and implications of the EU as a global security provider. This enables member states to reflect collectively on the EU role in the world and to learn how and why values, responsibilities, and priorities can be aligned. They are evident in roadmap documents like the EU Global Strategy 2016 and the Strategic Compass (European Union, 2022), which aim to enhance a shared understanding of European strategic environments and support priority-setting for defense efforts (Tardy, 2019; Lawrence, 2022).
By integrating perspectives, these forms of know-why promote a “common strategic culture” (ESDC, 2024a, 2024b). Yet, compared with previous findings from the U.S. case study (Ferreyra, 2025), it should be noted that the EU advanced training courses for senior-level officers place a more explicit emphasis on learning peacebuilding approaches and theories for understanding cooperation dynamics (ESDC, 2024e; Kmec, 2022). Reflecting competencies associated with the Athens model (Paile-Calvo, 2016), know-why is also evident in acquiring “the most advanced knowledge of international relations theory and the global security environment and architecture” (ESDC, 2021, p. 29). Advanced training courses further illustrate how cause-and-effect knowledge enable officers to “discuss the interaction among crisis management structures before and during planning for a response to a crisis” (ESDC, 2023, p. 9). For EU Operation Commanders, appointed at the military-strategic level to head designated OHQ (European External Action Service, 2019), know-why supports their ability to manage “the restraints, constraints, and capabilities” required for military operations as well as interoperability needs (ESDC, 2021).
Strategic Know-How
While know-why helps build common analytical frameworks within CSDP, its transformation processes also combine managerial and applied knowledge in strategic interoperability. According to ESDC qualification frameworks, officers serving at strategic level should possess “the most advanced knowledge of employing joint/national and multinational military organizations in a complex, unpredictable, and continuously evolving, multifaceted, politically led operating environment” (ESDC, 2021, p. 22; see also ESDC, 2024b). CSDP strategic-level officers must also manage staff and influence political decisions regarding the employment of military instruments in diverse circumstances (European External Action Service, 2021; ESDC, 2023, p. 2). Strategic-level know-how is often reflected in tacit abilities developed through experience.
Although EU formats differ from those observed in the U.S. context (Ferreyra, 2025), the CSDP also requires “leader-mediators” capable of articulating strategic perspectives and interests within the community of inquiry. As ESDC documents emphasize, officers should be able to apply “innovative mediation and negotiation theories/strategies to address highly complex issues across multiple stakeholders” (ESDC, 2021, p. 26). Other relevant competencies include leadership, critical thinking, and strategic communications (e.g., briefing techniques). Officers at this level are also expected to “making decisions within an integrated context, meeting the imperatives of adaptation and innovation in joint, combined operations, with a medium and long-term vision for the organization” (ESDC, 2021, p. 44; see also European External Action Service, 2021).
Strategic Know-Who
ESDC advanced training at the military-strategic level demonstrates the relevance of know-who and what Lundvall (2006) terms combinatorial knowledge for strategic interoperability. For instance, ESDC courses promote a “constructive organizational culture where different competencies and backgrounds are considered and used in a complementary way” (ESDC, 2022, p. 3). This also involves knowing the “roles and responsibilities of crisis management structures in planning” (ESDC, 2023, p. 9).
As also observed in the U.S. context (Ferreyra, 2025), strategic know-who, often tacit and highly localized, relies on leaders who can identify, complement, and leverage the expertise of diverse partners, services, and systems. Yet, compared with the U.S. case, CSDP command structures show significant differences in their access to know-who from other partnering organizations (ESDC, 2024b). In EUFOR’s Operation Althea in Bosnia and Herzegovina, for example, the EUMS agreed to use NATO’s SHAPE as the EU’s OHQ. This arrangement provided access to NATO’s planning expertise and capabilities, fostering combinatorial knowledge between the EU and NATO (Arjona, 2022). ESDC courses also implicitly invoke know-who in their learning outcomes, such as understanding “different perspectives and demands on senior military leaders” (ESDC, 2022, p. 2) and perspectives “both from actors in the host country, including civil society, and from permanent headquarters in Brussels” (ESDC, 2022, p. 4).
Operational Level
The operational level of executive CSDP-military operations concerns the employment of forces across an entire theater of operations. Command and control arrangements at this level are not permanent; the EU designates an ad-hoc Force Commander and Force Headquarters that will deploy to the area of operations on land or sea (European External Action Service, 2019).
Operational Know-What
While strategic know-what encompasses a broad informational and relational exchange across institutions and frameworks, operational know-what tends to be more contingent on specific operational environments. In peace operations more broadly, such as those conducted under UN integrated missions, information-sharing at the operational level often includes civilian contributions and instructions for military components (see, for example, Ferreyra 2025, p. 19). In the CSDP planning cycle of operations, information-sharing between civilian and military services at the operational level can be significantly different. Most CSDP operations do not establish civil-military chains of command. In CSDP structures, this explains the typology of military operations versus civilian mission, where the staff work is entrusted to separate command chains (Mattelaer, 2010, p. 7; Tardy, 2019).
Naturally, EU military operations and civilian missions collaborate and share information more closely when they are present in the same country. For instance, in Somalia, EUNAVFOR Operation Atalanta has actively exchanged data with its “sister missions“, EUCAP-Somalia and EUTM-Somalia (EUNAVFOR, 2025b). By participating in forums such as Shared Awareness and De-confliction (SHADE), know-what (e.g., information on maritime security, illicit activities) supports a coordinated and integrated approach.
However, various challenges for peaceweaving remain in terms of civil-military “operational synergies“, particularly in efforts “to make the whole larger than the sum of its parts” (Zartsdahl, 2018, p. 201). Furthermore, FIMI campaigns can significantly deteriorate peaceweaving. By seeking to damage the reputation of EU operations – often by misleading populations in partner countries about their role and mandate – FIMI in conflict-affected areas can particularly damage vertical and diagonal relationships between EU Force Headquarters and local actors (Fridman et al., 2023). To counter disinformation, EU staff absorb various forms of know-what (e.g., intelligence, situational awareness reports) and employ instruments known as the FIMI Toolbox to strengthen local analytical capacity regarding disinformation (ESDC, 2021; ESDC, 2024d).
Operational Know-Why
EU operations are commonly framed within peacebuilding theory as an expression of theoretical know-why (e.g., Kmec, 2022). This brings EU staff on the ground relatively closer to UN interpretative frameworks rather than to U.S. stabilization approaches (Ferreyra, 2025). Here, effective interoperability requires a deep understanding of “key principles of integrated approaches“, incorporating political, humanitarian, and development dimensions of peacebuilding, as well as cross-cutting security challenges (ESDC, 2021, p. 54; ESDC, 2023). Beyond generic issues such as “the impact of new technologies on military organizations and interoperability” (ESDC, 2022, p. 5), EU-peacebuilding frameworks demand a focus on sympathetically understanding host-country needs (ESDC, 2022). This supports aspects of diagonal interoperability and activities such as capacity-building and training of local forces (e.g., EUNAVFOR, 2024).
EU training in operational planning highlights cause-and-effect knowledge as staff-officers must learn “how local/national, regional, and global issues are related to all phases of the conflict cycle and are relevant to prevention, crisis response/management, stabilization, and long-term peacebuilding” (ESDC, 2023). This includes understanding how joint operations with certain host-country forces could affect the impartiality of EU troops in the perspective of vertical interoperability with local citizens (e.g., IECEU, 2017, p. 66). From a horizontal-interoperability perspective, officers require know-why to interpret the implications and controversies that arise when diverse cultures interact (ESDC, 2021, p. 58). In this sense, know-why helps to understand underlying issues in peaceweaving, such as national caveats and differing interpretations in operational activities (Sabatino et al., 2023).
Operational Know-How
The know-why described above orients and improves the practical performance of interoperability (know-how) in key operational functions. Officers should be able to implement the EU integrated approach “through cooperative problem-solving and teamwork” (ESDC, 2023, p. 2). Coordination also demands analytical skills to “evaluate the distinct and overlapping roles between civilian and military institutions as part of the security sector of a nation, and at the supranational level, under political supervision and civilian oversight” (ESDC, 2021, p. 40). Commanders and staff should “manage the processes of strategic communication“, applying “tools and methods of cross-cultural and gender-responsive internal and external communication” (ESDC, 2022, p. 2).
Commanders use the critical thinking of leader-mediators to detect potential problems and find ways to improve “the degree of interoperability between the HQs and forces and to integrate all participating units” (European External Action Service, 2019). Commanders also should be able to “critically evaluate the capabilities of command, control, communications, computers, intelligence, surveillance, reconnaissance, and cyber defense systems and integrate their requirements in the planning and conduct of multinational operations” (ESDC, 2021, p. 40). EU training materials also indicate the importance of learning interpersonal skills that foster respect and confidence while chairing consensus-based meetings, as well as the role of communication skills to build trust and provide clarity in uncertain contexts (ESDC, 2021; 2022, 2023).
Operational Know-Who
Following Lundvall (2006), know-who is a crucial component in the formation of relationships with other specialists and leveraging their expertise. At the operational level, examples of know-who can be seen in the learning outcomes of EU training programs and qualification frameworks that emphasize the understanding of competences and perspectives across services, branches, and agencies, including NGOs, and IGOs, as well as host-nation perspectives at regional and local levels (European External Action Service, 2021; ESDC, 2021). Know-who also underpins abilities such as “cooperating, building, and using networks with partners and stakeholders on the ground and at the EU level, as outlined in the EU Integrated Approach” (ESDC, 2022, p. 3).
In Force Headquarters and mission-level command structures, understanding others’ capabilities is crucial for “critically assessing service-specific (land, maritime, air) force capabilities, organizations, and activities conducted as part of a joint force” (ESDC, 2021, p. 33). Through these practices, operational know-who helps officers to transform constraints such as bureaucratic divisions or mandate boundaries into opportunities for enhanced interoperability and collaborative problem-solving.
Tactical Level
The tactical level of CSDP operations involves individual engagements or the employment of EU-led force components in the area of operations (European External Action Service, 2019). Officers lead and operate within combined-arms sub-units, advise and support higher-level commanders, supervise training, and command branch-specific units (such as platoons), among other activities.
Tactical Know-What
EU training documents indicate that CSDP tactical units should be able to “combine in-depth and detailed information on the military domain” (ESDC, 2021, p. 28), which can be a prerequisite for peaceweaving in deployment contexts. Know-what supports “tactical mission planning at the small team/sub-unit level, making use of specific and relevant operational terms and graphics in order to achieve higher-echelon objectives” (ESDC, 2021, p. 34). In horizontal interoperability between units, one sees, for example, how EUNAVFOR’s Operation Irini and Operation Aspides are being used to strengthen information-sharing at sea – including intelligence and the Recognized Maritime Picture – through the MARSUR system, improving situational awareness between navies (EUNAVFOR, 2025a). In terms of diagonal interoperability, EUFOR’s Operation Althea has shown how sharing security assessments and briefings on landmine and explosive remnants of war (ERW) threats with Bosnian police and military units helped protect civilians while developing diagonal relationships. Engaging citizens in ERW information-sharing – visiting schools, associations, and clubs – has likewise proved relevant to vertical interoperability (EUFOR, 2025; Sabatino et al., 2023).
Tactical Know-Why
Previous EU operations have shown how peaceweaving often involves meaningful engagements with local actors. For instance, EUFOR CAR documented how communities in the Central African Republic recognized relationships of trust with troops on the ground (IECEU, 2017). In such contexts, know-why matters to communities of inquiry in several ways. Troops must discern, for example, the effects of their own behavior and the kinds of attitudes required for secure relationship-building and stabilization efforts (ESDC, 2024c; see also Mattelaer, 2008).
EU training courses emphasize the influence of cultural and gender dynamics in relationships (ESDC, 2021; 2022). Furthermore, deployments often involve engagements in conflict zones affected by war crimes, human rights violations, sexual violence, and other abuses, in which the military can also be implicated (De Coninck, 2023). If different groups – men, women, and children, for example – are differently affected by conflict, know-why is useful for recognizing how. The cognitive integration of gender, cultural, and human rights dimensions affords a better determination of which forms of mediation, negotiation, and dialogue (know-how) may be more effective (ESDC, 2024c). This knowledge also supports horizontal and diagonal interoperability on the ground by enabling a deeper understanding of the ethical implications of confident, supportive, trustworthy, and loyal relationships between various officers.
Tactical Know-How
Peaceweaving skills in CSDP-deployments often align more with the Athens model rather than expertise in equipment and weapons, a tendency also observed in my previous study (Ferreyra, 2025, p. 25). This emphasizes adaptive and sympathetic skills to deal with the complexity of the social, economic and political aspects of their mission. As emphasized in EU training curricula, tactical-level officers should be adaptable to change and maintain an open attitude toward intercultural interactions (ESDC, 2024c; see also ESDC, 2021). Units are encouraged to develop “sensitivity to the challenges of applying ADR [alternative dispute resolution] techniques” (ESDC, 2024c, p. 2) fostering metacognition and self-reflection in their interoperability practices (ESDC, 2021). At this level, competent commanders should be able to “apply the relevant skillset (analysing, questioning, reformulating, empathic/active listening)” while remaining aware of interpersonal dynamics and gender considerations (ESDC, 2021, 2024c, p. 2). Overall, these sympathetic know-how abilities help create interactive environments for effective cooperation both within a military structure and in engagements with local actors and stakeholders (ESDC, 2024c, p. 2).
Tactical Know-Who
Local actors are often those who best understand intrinsic societal dynamics, and access to this local know-who can be essential for navigating and interoperating in operational contexts. For instance, Atalanta naval forces recognized how close dialogue with local seafarers improved their understanding of maritime activities and helped identify the local “pattern of life” (EUNAVFOR, 2024). EUFOR’s Operation Althea similarly relied on Liaison and Observation Teams (LOTs) embedded in communities throughout Bosnia and Herzegovina, enabling forces to “feel the pulse” of the situation (EUFOR, 2025). Yet some analyses argue that local expertise is not always fully leveraged in EU operations, limiting the timely or effective use of these forms of knowledge (e.g., Sabatino et al., 2023).
From the perspective of horizontal interoperability, EU training materials also highlight the importance of tactical know-who, as officers should sympathetically understand the traditions and working cultures of different arms, branches, and units, including small teams, in both national and international contexts (ESDC, 2021; ESDC, 2021, p. 43).
Knowledge Forms and Their Relevance Across Interoperability Levels
A comparative analysis of the U.S. case indicates that the relevance of the four knowledge categories varies across the strategic, operational, and tactical levels of interoperability (Ferreyra, 2025): their relevance, that is, is not homogeneous across the three echelons, and the focus and scope of interoperability tend to vary at each level. In the present study of EU peace operations, I find that these variations align with trends observed in CSDP structures and their military levels of operability and training requirements (e.g., ESDC, 2021, 2022, 2023, 2024a, 2024b, 2024c; EU, 2020b; Paile-Calvo, 2016). Table 3 sets out the correspondence between the knowledge types and the examples most salient at each level in the analysis of EU CSDP peace operations. From a pragmatist perspective, these variations reflect how communities of inquiry mobilize knowledge differently to resolve the distinct problems that emerge at each level of interoperability.
Table 3
Relevance of the Knowledge Categories Across the Levels of Interoperability.
| LEVEL | CATEGORY | EXAMPLES |
|---|---|---|
| Strategic | Know-Why | EU values on security and multilateralism, integrated approach principles; EU priorities and long-term goals |
| Know-How | Strategic planning; strategic thinking; political-military coordination; negotiation; critical thinking | |
| Operational | Know-Who | Understanding service-specific capabilities and leveraging their expertise |
| Know-How | Coordination and communication skills for joint/multinational operations | |
| Tactical | Know-How | Teamwork; intercultural interaction; adaptive skills; empathic/active listening |
| Know-What | Mission planning data (terms, graphics); sharing mine/ERW threat information with citizens |
Overall, both previous findings from the U.S. interviews and EU official and training documents and analyses suggest that, as the level of command and decision increases, reflexivity, critical thinking, and abstraction become more important for addressing cross-cutting problems in organizations. In line with interoperability studies sponsored by the ESDC (Paile-Calvo, 2016, p. 8), activities at the strategic level are often conditioned by the maturity and experience of “senior-level” officers (see Ferreyra, 2025). For these officers, interoperability has a broader, often more conceptual scope, entailing value alignment between partners, worldviews, and long-term goals such as those articulated in the CSDP and the EU Global Strategy on Foreign and Security Policy (e.g., ESDC, 2024a, p. 2). In contrast, the junior officer, often deployed soon after commissioning, “may not necessarily require from them in-depth knowledge and command of the strategic level’s arcana in a first place, as they would play a role in the decision making of the international organisation only at senior level in their career” (Paile-Calvo, 2016, p. 8).
At the tactical and operational levels, interoperability activities tend to focus on joint operations and specific tasks with a more immediate scope (see, for instance, European External Action Service, 2023, pp. 126–127; Markel et al., 2011). For these reasons, know-why becomes particularly important at the strategic level of interoperability (also Ferreyra, 2025), where it enables the development of senior-level officers’ specialized expertise, characterized by elements such as strategic thinking, analytical skills, leadership and creativity in navigating diverse interagency and organizational settings (see, for example, ESDC, 2024a; Ferreyra, 2025). It can be seen that this interplay between know-why and know-how helps define this level and distinguishes it from the lower echelons of interoperability.
According to the empirical material, at the operational level military commanders and staff officers will be increasingly in contact with multiple units and inter-agency actors (see, for example, ESDC, 2022; ESDC, 2021; Markel et al., 2011; Ferreyra, 2025). In this context, interoperability activities reflect what Lundvall (2006) calls “interactive learning” and engagement with diverse specialists and their expertise (know-who) conducted in order to coordinate operations. For planners, know-who is essential for linking and combining disparate elements of know-how. Knowing-who thereby supports and complements abilities in coordination and planning across various timeframes, professional domains, and perspectives (e.g., ESDC, 2022, 2023). Due to the greater emphasis on working with and leveraging others’ knowledge, know-who forms of knowledge can be considered more relevant at the operational level.
At the tactical level, interoperability primarily concerns the execution of assigned tasks and the employment of units, where know-who can be less relevant. This is partly because the scope of action is narrower (see, for instance, ESDC, 2021; European External Action Service, 2019; Markel et al., 2011). As observed in the study on the U.S. case (Ferreyra, 2025), officers and units often operate within clearly defined areas of responsibility, and there is often limited interaction with other elements, as units often work within their own sector or area. In these settings, effective performance in executing tasks depends on a primary focus on the application of practical knowledge (know-how); these requirements are notably supported by specific know-what, ensuring a shared understanding of what needs to be done in activities and procedures (see, for example, ESDC, 2021, pp. 16–19; ESDC, 2024c, pp. 1–3). Although diverse forms of know-why are not absent, there tends to be less need for reflection: operational and strategic thinking attitudes are relatively less relevant.
Concluding Discussion
As observed through CSDP structures, different forms of knowledge help develop interoperability in EU peace operations. The main hypothesis was supported by the finding of Lundvallian categories at all three levels of interoperability, with a different order of relevance at each. Comparative insights from previous research on the U.S. case served as an analytically grounded point of reference for addressing these categories and their variation within the EU context. I found similar patterns of knowledge relevance across the CSDP organizational levels, which helped clarify common challenges (value alignment at the strategic level, for example, or the difficulty of linking and combining disparate elements of know-how at the operational level) as well as key lessons and context-specific solutions.
Many of these challenges emphasize the “art of working with differences” as a core organizational and individual faculty. Abilities to collaborate across existential, cultural, functional and organizational differences, rather than among actors who share a common heritage, function and/or belief system, support the principles of peaceweaving and various practical forms of sympathetic knowledge, which inherently involve an openness to multiple ways of thinking and doing within communities of inquiry.
The distinctions made and the results obtained offer practical recommendations for military education and training institutions that can be considered both in EU and NATO contexts. They help to clarify the relationships between specific forms of knowledge and levels of interoperability in military organizations, as well as how best to communicate them from practitioners to relevant decision-makers. The taxonomy can also serve as a framework to organize “learning outcomes” in training programs, as observed in ESDC training documents (e.g., ESDC, 2022). It can also be applied in qualifications frameworks to organize competence area by learning area in tabular formats (e.g., ESDC, 2021). Sympathetic knowledge and its practical forms can inform the design of the training program as a tool for harmonizing competencies in interoperability and for developing matrices that connect competencies and functions of soldiers and peacekeepers.
However, some limitations must be acknowledged. Most notably, I did not conduct interviews with CSDP-military officers, which would have provided insights relevant to the EU case study. While ESDC training materials and EU documents contain rich and valuable insights, future research could build on those findings by developing EU contacts and conducting interviews.
Furthermore, while the knowledge required for interoperability can vary depending on the nature of operations, the findings of this study reflect perceptions and professional experiences within the normative context of peace operations. Large-scale combat operations, for instance, may demand know-how sets different to those necessary for peacekeeping. The diagonal/vertical component of interoperability is often overlooked in other contexts (see, for example, Ferreyra, 2025) and obtaining knowledge through local relationships (know-who), for example, can be particularly difficult.
Despite the contextual differences, similar patterns can also be observed across different types of military operations. For instance, the three standard levels of operability (“levels of war”) and related-doctrinal factors remain important, often demonstrating a similar understanding across different military operations. This helps us to understand the potential relevance of the findings here to matters beyond the immediate context of case studies.
This study adopted an exploratory approach affording flexibility for the testing of new ideas and perspectives (see, for example, Stebbins, 2001). The study offers initial, non-conclusive insights into the forms of knowledge that support effective military interoperability. Future research may further explore both the mechanisms through which these forms of knowledge are generated, shared, and transformed, and the models of interoperability emerging from different knowledge management practices.