The concept of discontinuity in project marketing research: emergence, dissipation and glimpses of the future

Purpose – This study aims to focus on a speci ﬁ c project marketing concept, i.e. “ discontinuity, ” and analyzes how this concept emerged in project marketing, becoming its key scholarly embodiment, how it became decoupled from the increasingly service-intensive project business practice and what the relevance of discontinuity is for project marketers moving forward. Design/methodology/approach – This study is built on a systematic literature review of 31 years (1993 – 2023) of publishing data from major marketing and management journals. Findings – This study provides three ﬁ ndings. First, the author reveals the risks related to marketing scholars and practitioners losing sight of each other as business practices evolve much faster than scholarly research can keep up. Second, the author highlights the role of interdisciplinary collaboration in advancing conceptual innovations. Finally, the research elucidates the need for broader metatheoretical re ﬂ ection to keep this research tradition on an upward trajectory. Research limitations/implications – The aim of this study is not to criticize project marketing, as many strands of business-to-business (B2B) marketing face the same challenge, but to elucidate a need for conceptual innovations, collaboration with practitioners and other disciplines and broader metatheoretical re ﬂ ection to keep this research tradition on an upward trajectory. Originality/value – This study makes several contributions to the project marketing research tradition. First, it reviews the emergence and dissipation of the concept of discontinuity, drawing on semantical, etymological and epistemological insights. It also re ﬂ ects on recent disruptions in the marketplace and envisions future research trajectories for this elusive concept. In addition, the author develops a conceptual framework that combines project types with exchange elements in project and service businesses. This conceptual framework helps elucidate what part of the exchange is continuing and what is discontinuing in the resulting business relationships. Furthermore, the research contributes to B2B marketing more broadly by highlighting the ﬂ eeting correspondence between theory and the real world. It underscores the need for constant updates to maintain relevance.


Introduction
It has taken a long time for mainstream marketing scholars to recognize the importance of projects (Hadida et al., 2019), even though projects are commonly used to organize marketing activities in areas such as advertising (Grabher, 2004) and new product development (Ibert, 2004;Massey and Kyriazis, 2007).In contrast, business-to-business (B2B) marketing scholars have always needed to sell and understand the value of complex projects and solutions (Macdonald et al., 2016).Indeed, projects are becoming increasingly important for marketers, as the world is gradually turning into a "project society," where even the most long-standing institutions are subject to temporary forms of organizing (Lundin et al., 2015).
The eclectic word "project" has various meanings depending on the context in which it is applied, referring often either to work organized through projects (Packendorff, 2002;Whitley, 2006) or to a transaction between a project buyer and seller (Cova and Salle, 2005).In the latter case, project refers more broadly to project business and the exchange of project offerings (Artto and Wikström, 2005), so "project marketing" is needed to safeguard the transaction through its various stages (Cova and Holstius, 1993).Project marketing developed from B2B marketing relatively recently, as the earliest related works were published in the early 1990s (Bansard et al., 1993;Cova et al., 1994;Hadjikhani, 1996).The aim of project marketing involves creating, maintaining and managing relationships that support forthcoming project demand (Cova and Hoskins, 1997;Cova et al., 1994;Tikkanen et al., 2007).As such, the ethos of project marketing is relational, and project marketing can be defined as the process of managing project buyer-seller interactions throughout project stages within a network context (Cova and Holstius, 1993;Jalkala et al., 2010).
Projects include various stages that can be defined in detail (Cova and Holstius, 1993) or more broadly as the preproject, project and postproject stages (Engwall, 2003).In each project stage, various professionals and organizations are assembled temporarily (Blomquist and Wilson, 2007;Lundin and Söderholm, 1995), potentially leading to a loss of customerspecific knowledge between project stages and coordination challenges (DeFillippi and Arthur, 1998;Prencipe and Tell, 2001).Furthermore, projects do not occur in isolation (Engwall, 2003); rather, they are embedded in networks that interlink various projects and relationships (Artto et al., 2008a;DeFillippi and Sydow, 2016).Project marketers need contextual and historical understanding of projects to identify and comprehend these complex links (Håkansson and Snehota, 2006).Therefore, project marketing is a very challenging discipline in terms of management.
Project buyer-seller relationships typically hinge on large industrial projects such as those in aerospace, shipyards and engineering, requiring multibillion investments and careful consideration from both buyers and sellers (Jalkala et al., 2010).However, not all projects are multibillion mega-projects.Other contexts include movie productions (Faulkner and Anderson, 1987), construction projects (Havenvid et al., 2016b;Winch, 1998) and other temporary settings employing a large number of freelancers (Meyerson et al., 1996), such as virtual marketing teams (Thrasyvoulou, 2010).Projects can vary in terms of their technological uncertainty and system complexity (Shenhar, 2001), milestone visibility, client involvement and technical cumulativeness (Whitley, 2006) and in the scope of services integrated into the project delivery (Momeni and Martinsuo, 2019).Project marketing is, therefore, contingent on contextual and project characteristics, which demand managerial attention.
The conceptual foundations of project marketing are built around the D-U-C framework, which was coined in the mid-1990s to elucidate the unique characteristics of project marketing in comparison to other B2B marketing (Cova et al., 2002;Cova and Hoskins, 1997;Mandj ak and Veres, 1998;Skaates et al., 2003;Skaates et al., 2002).In the framework, "D" represents discontinuity, "U" uniqueness and "C" denotes project complexity.Of these three elements, discontinuity (D) has received the most attention (Hadjikhani, 1996;Mandj ak and Veres, 1998;Skaates et al., 2002;Skaates et al., 2002).Indeed, it has been argued that discontinuity is the most important strategic concern in project marketing (Cova et al., 2019;Cova and Salle, 2007;Hadjikhani, 1996;Jalkala et al., 2010;Skaates et al., 2002).Discontinuity experienced in the postproject stage filters into the potential preproject stage in a sequential project delivery to the same customer (Artto et al., 2008a;Skaates et al., 2002).Indeed, there are two "nested" levels of project marketing: the first relates to individual projects and their relationships and networks, whereas the second level comprises sequential project deliveries, including dormant periods without any project activity (Alajoutsijärvi, 1996, p. 268).Thus, is there a downside to the D-U-C framework?
Even though projects have expanded in scope, the uniqueness (U) and complexity (C) aspects of the framework remain accurate (Jalkala et al., 2010).However, the first element of the framework (D) needs to be amplified.Broadly speaking, project discontinuity refers to the sporadic nature of project exchanges and difficulty in predicting project sales (Bansard et al., 1993).Project marketers have, thus, sought to manage discontinuity to assure prospective project sales (Cova and Salle, 2007;Hadjikhani et al., 2012;Jalkala et al., 2010).However, the novel service business revenue streams (Artto et al., 2008b;Davies et al., 2007;Kujala et al., 2013) and the resulting extended project life cycles (Artto et al., 2016;Momeni and Martinsuo, 2019;Wikström et al., 2009) seem to have influenced project business practices, potentially eroding the phenomenon of discontinuity."Servitization" refers to companies offering bundles of knowledge, services and products where the customer pays for the usage of the service rather than the equipment (Vandermerwe and Rada, 1988)."Postproject" services include various add-ons that are delivered to customers after project handover, increasing the duration and stability of exchange (Ojansivu et al., 2015).
In recent years, scholars have given noticeably less attention to project marketing in terms of conference presentations, dedicated conference tracks and journal articles in prominent B2B marketing journals.The aim of this research is to determine what has caused such stagnation.Is it possible that project marketing has gone through an "academic drift", referring to the process whereby the practical applicability of knowledge gradually diminishes while it becomes more closely intertwined with a purely academic perspective (Corbett and Van Wassenhove, 1993;Harwood, 2010)?We believe that discontinuity as the key concept and the lightning rod of the discipline can elevate such insights.Indeed, Blumer (1954, p. 5) corroborates that: [. ..] everything [in science] depends on how fruitfully and faithfully thinking intertwines with the empirical world of study, and since concepts are the gateway to that world, the effective functioning of concepts is a matter of decisive importance.Thus, we pose the following three questions: RQ1.How and why did the concept of discontinuity emerge in project marketing, becoming its key scholarly embodiment?
RQ2.How does the increasing use of postproject services influence discontinuity?
RQ3.What is the relevance of discontinuity for project marketers moving forward?
Within this literature, three prevalent discontinuity themes emerged: 1 discontinuity as irregular demand; 2 discontinuity as sleeping relationships; and 3 discontinuity as mitigated by services.
In addition, we focused on the different terms and semantics that scholars use to express discontinuity in the literature.
Our study contributes to project marketing research in the following ways.First, we elucidate the etymology of the concept of discontinuity and its various meanings, capturing the zeitgeist of 31 years  of project marketing research.Second, we envision future directions for project marketing research in the changing project business environment.Third, we develop a conceptual framework that clarifies what part of the exchange is continuing and what is discontinuing in business relationships across different project types.This conceptual framework is valuable for managers as it makes the discontinuity characteristics visible in the project buyer-seller interface.In addition, our research makes three broader contributions to B2B marketing.First, we unearth the risks associated with marketing scholars and practitioners losing sight of each other as business practices evolve more quickly than scholarly research can keep up.Second, we illustrate the role of interdisciplinary collaboration in advancing conceptual innovations.Finally, we highlight the need for broader metatheoretical reflection to maintain the upward trajectory of this research tradition.
This article is structured as follows.Section 2 outlines the literature search strategy used for the systematic review of 31 years  of project marketing publications in major marketing and management journals.In Section 3, the emergence and dissipation of the concept of "discontinuity" is analyzed by drawing semantical, etymological and epistemological insights and reflecting upon recent disruptions in the marketplace.Section 4 develops a theory about business relationship discontinuity in different project types.Finally, in Section 5, the author concludes by discussing the future of project marketing research and proposing implications for both research and practice.

Research method
This article focuses on a rather unknown strand of B2B marketing that could add value and provide insights for marketers in a "project society" (Lundin et al., 2015): project marketing.The decision to immerse oneself in one rich literature "case" is supported when there is limited knowledge about the phenomenon, necessitating a rich longitudinal analysis, and when the aim is to provoke new ideas (Siggelkow, 2007).The aim was to research how the concept of discontinuity emerged in project marketing, how it became its key scholarly embodiment and how it eventually clashed with increasing service-driven project businesses.

Search strategy
A systematic three-step review was conducted as suggested by Tranfield et al. (2003).First, the aims and the main data sources of the review were determined.The sources were limited to peer-reviewed articles from marketing and management journals authored in English and published before February 17, 2023, which yielded appropriate and impactful sources of knowledge (Reid and Plank, 2000).The following four most comprehensive marketing and management study databases were chosen: Business Source Complete (EBSCO), ProQuest (ABI/INFORM), Web of Science and Scopus.Second, the search terms were identified, the inclusion criteria of the data were decided and the data were synthesized (Tranfield et al., 2003).The literature research commenced with a keyword search covering the titles, abstracts and the main body of articles in the four selected databases.

Sample selection
With the initial search term "project marketing", 63 articles in EBSCO, 74 articles in Scopus, 44 articles in Web of Science and 272 articles in ProQuest were located.Then, the number of articles was narrowed down through an examination of the full articles and a focus on the specific use of the concept of discontinuity.In project marketing, discontinuity has been conceptualized in the following two ways (Mandj ak and Veres, 1998;Skaates et al., 2002): 1 broadly as irregular project demand; and, more explicitly, 2 as the postproject stage embodying social ties in the absence of contractual agreements.
In the latter case, the interaction is characterized as a "sleeping relationship" (Hadjikhani, 1996).Thus, articles that used either of the terms discontinuity or sleeping relationship were included.As an outcome of this process and after crosschecking, a total of 58 articles were retained.Then, 2 articles that the search engines had not recognized but were identified during the review (indicated by 1 in Table 1) were added, resulting in a final set of 60 articles.Figure 1 provides an overview of the literature review process.

Data analysis
Next, each of these articles was systematically coded to determine whether discontinuity was referred to as "irregular demand" or "sleeping relationships" (Mandj ak and Veres, 1998;Skaates et al., 2002).Most papers that used the concept of a sleeping relationship also mentioned discontinuity, but the papers categorized as "irregular demand" discussed the discontinuity phenomenon more broadly without explicitly using the sleeping relationship concept.This article also identified when and how services became a part of the project marketing literature.The term "services" was searched in the articles to determine when services emerged and how they were affiliated with discontinuity.
The goal of the final and third step of the literature review was to distinguish emergent themes, aggregate links among themes and summarize the original literature (Tranfield et al., 2003).Table 1 presents the results of the literature search, including a list of the articles and their coding.

Analyzing the emergence and dissipation of the concept of "discontinuity"
3.1 Insights from the semantics used to express discontinuity in the literature 3.1.1The emergence of the discontinuity phenomenon (1993)(1994)(1995)(1996) In the first chronological phase, the theme of "discontinuity as irregular demand" is prevalent, as the language used to express discontinuity relates to the marketplace and to the economic realities of the project business.In the original paper from Bansard et al. (1993), terms such as anticipation capacity, nonrenewable relations, foreseeing exchanges and instability are used to frame discontinuity as a phenomenon.Similar kinds of demand-related language continue in the following years and include need conversion, absence of demand, postponed demand and cyclical downturns (Bonaccorsi et al., 1996), discontinuity of incoming orders, financial shortages and financial outlays (Günter and Bonaccorsi, 1996).

3.1.2
The establishment of sleeping relationships as a unique embodiment of discontinuity (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006) During the second chronological phase, the theme "discontinuity as sleeping relationships" gained momentum, and terms used to describe discontinuity became more focused on the microlevel buyer-seller interaction during sleeping relationships and projects as episodes in the longer-term business relationship.Terms such as life after project completion and no contractual agreement (Hadjikhani, 1996), relationship termination and aftermath stage (Alajoutsijärvi et al., 2000), extrabusiness relationships, project marketing horizons, milieus and rituals (Cova and Salle, 2000), two nested levels of industrial projects (Alajoutsijärvi, 1996;Skaates et al., 2002) and projects as episodes within more enduring relationships (Welch, 2005) became the key tenets of the academic parlance in project marketing.

3.1.3
The unfolding of the discrepancy between discontinuity and postproject services (2007)(2008)(2009)(2010)(2011)(2012)(2013) Over time, new scholars entered project marketing and began to pinpoint discrepancies between discontinuity and postproject services during the third chronological phase, which led to the theme of "services mitigating discontinuity" becoming widespread in project marketing research.The terms used to express discontinuity became almost its antidote and included carry-over, after-sales services and dozing relationships (Blomquist and Wilson, 2007), total solution, long-term support and long-term relationships (Owusu et al., 2007), in-between projects, add-on services and complementing project deliveries with services (Tikkanen et al., 2007), turnkey projects, extended timescale and after sales services (Ahola et al., 2008), stability of revenues and enhancing continuity through services (Kujala et al., 2013), postproject buyer-seller interaction dynamics and continuous service exchange revenue streams (Ojansivu et al., 2013).

The stagnation of discontinuity research (2014-2023)
Toward the end of the fourth chronological phase, the language used to portray discontinuity became more implied and less tied to the original strategic objectives of project marketing.Some scholars used discontinuity almost like a placeholder to contextualize research, often through the DUC framework, rather than to address pertinent matters in project marketing.Scholars applied terms such as demand milieu and future demand anticipation (Crespin-Mazet et al., 2019), economic discontinuity and latency period (Cova et al., 2019), project contract life-cycle and active postproject relationship (Turner et al., 2019), life-cycle solutions and extended project life-cycle (Momeni and Martinsuo, 2019).Interestingly, all articles published from 2020 onward fit into the "discontinuity as irregular demand" theme with terms such as low frequency of sales (Ståhle and Ahola, 2022), discontinuities of market transactions and competitive bidding procedures (Crespin-Mazet et al., 2021), aftermath stage (Holma et al., 2022) and project transition (Bizarrias et al., 2020).It almost seems that project marketing has returned to the first phase (1993)(1994)(1995)(1996) in terms of its semantics.
3.2 Insights from the etymology of the concept of "discontinuity" An analysis of both Table 1 and Figure 2 simultaneously reveals that the concept of discontinuity was first coined in the project marketing literature in 1993 by Bansard et al. (1993).Three years later, Hadjikhani (1996) conceptualized sleeping relationships as a unique embodiment of discontinuity in project marketing.Hadjikhani (1996) argued that even though discontinuity was quite usual in business relationships, it caused considerable difficulties for project marketers.Moreover, resource exchange was expected to end shortly after project delivery as the contractual duties ceased.The nature of the interaction changed, and the relationship turned into a sleeping relationship.
Importantly, sleeping relationships provided a distinct identity for project marketing researchers: "The introduction of sleeping relationships is an effort to differentiate project marketing from other industrial relationships" (Hadjikhani, 1996, p. 334).Several papers focused on different aspects of sleeping relationships (Cova andSalle, 2000, 2005;Morabito et al., 2005;Skaates et al., 2002;Welch, 2005); thus, sleeping relationships became a key concept in project marketing.Over time, the use of the sleeping relationships concept expanded from project marketing to other strands of marketing, as demonstrated by the 236 citations of Hadjikhani's (1996) article on Google Scholar.Concurrently, the meaning of the concept has become more diluted and less affiliated with its original definition.
In mid-2000, the services literature started to become mainstream in marketing (Brax, 2005;Vargo and Lusch, 2004).Blomquist and Wilson (2007) were the first to explicitly note the discrepancy between the concept of discontinuity and the postproject service exchange.These authors found (2007, p. 216) that there was "significant carry-over after projects were competed in terms of after-sales service and maintenance" and, therefore, that the sleeping relationship concept was not fitting.In the following years, similar observations continued (Ahola et al., 2008;Jalkala et al., 2010;Kujala et al., 2013;Ojansivu et al., 2013;Ojansivu and Alajoutsijärvi, 2015;Owusu et al., 2007;Sariola and Martinsuo, 2015;Tikkanen et al., 2007), as shown by the steep curve in Figure 2 following the year 2007.
For example, Artto et al. (2008aArtto et al. ( , 2008b, p. 503, p. 503) noted that a "project is an entry point so that the customer will be interested in future services."The buyer-seller dynamics in projects were changing.
Many project businesses, including elevators and escalators, railroad transport industry, energy generation, construction and offshore oil and gas, were progressively earning more profits from project-related services than from the projects (Alderman et al., 2005;Davies, 2004;Gebauer et al., 2010;Salonen, 2011).For example, Alderman et al. (2005) found that in a 1.8bn euros (US$1.96bn)train project, a 12-year service agreement was worth 912m euros (US$992m).Therefore, projects were becoming a "Trojan horse" to seize increasingly lucrative service agreements.Recent project marketing research has continued to report similar findings (Aarikka-Stenroos et al., 2018;Crespin-Mazet et al., 2019;Görög, 2016;Momeni and Martinsuo, 2019;Turner et al., 2019;Turner and Lecoeuvre, 2017;Ulaga and Kohli, 2018).During these project business developments, the phenomenon of discontinuity has changed drastically, translating into interaction that does not resemble the sleeping relationship (Artto et al., 2015;Blomquist and Wilson, 2007;Ojansivu et al., 2015).This phenomenon can be observed in Figure 2 from 2013 onward, as each of the three research themes stagnated one after another, and 2016 marks the last year during which discontinuity is cited as sleeping relationships.In 2019, the irregular demand theme picked up again, but many of these articles remained quite loosely affiliated with core project marketing research.Consequently, the characteristics that justified project marketing triggered its consequent stagnation.Essentially, the characteristics of discontinuity (irregular demand and sleeping relationships) define project marketing.As the agreement between theory and empirical findings continued to decline (see "servitization" Baines et al., 2009;Brax, 2005;Vandermerwe and Rada, 1988), project marketing knowledge continued to lose its explanatory power.However, does that mean that project marketing has lost its research impact?

Insights from the episteme of project marketing
This brief history of project marketing illustrates that the explanatory power of theory is not absolute; instead, it is relative to the predominant circumstances.As time passes, these circumstances might change in such a way that the theory no longer captures the phenomenon.When "discontinuity" was introduced to project marketing in 1993 by Bansard et al. (1993), it marked a major conceptual innovation.This concept supported a departure from the B2B marketing assumptions regarding project buyer-seller interaction and a novel interpretation of the project marketing phenomenon.Project buyer-seller interactions were seen as distinctively twofold, including the individual projects and the relationships encompassing several projects with ingrained periods of discontinuity (Skaates et al., 2002).Hadjikhani (1996) empirically validated the "discontinuity" concept three years after it was introduced.More research followed, turning discontinuity, especially the "sleeping relationship," into a mainstream concept in project marketing.However, project marketing remained a niche strand in B2B marketing, limiting its ability to leave a long-lasting mark on marketing practice.For it to have a lasting impact, the value of discontinuity and sleeping relationships for the broader B2B marketing and project management audience and especially practitioners would presumably have needed to be further unpacked [1].
For almost a decade, project marketers had a distinct identity within B2B marketing.However, from 2005 onward, the services literature gained popularity, revealing the discrepancy between after-sale services and discontinuity.From 2007 onward, criticism was repeatedly leveled against discontinuity, and this concept slowly faded from the limelight.Project marketers were slow to adapt to the changing project business and envision a future in which the focus would shift from "the management of discontinuity to the management of continuity" (Jalkala et al., 2010, p. 132).As a result, the concept of discontinuity morphed from a conceptual innovation to an epistemic roadblock.Indeed, when industry practices change at a rapid pace, marketing knowledge needs to keep up and help people make sense of the new marketing reality, reinforcing their confidence in marketing.When knowledge stagnates, critical thinking and reflection are needed to keep the strand on a favorable trajectory (Alvesson and Spicer, 2019).Thus, where does this leave project marketers going forward?

Reflections on the disruptive developments in the marketplace
In 2020, COVID-19 disrupted the market, and abruptly, businesses around the world went into "hibernation" (Rogers, 2020).In Australia, the federal government launched a "hibernation policy" so that businesses could "sleep in" and revamp their operations after the crisis (Elmas, 2020;Kehoe, 2020).Suddenly, the entire global economy had to grapple with the same challenge with which project marketers were wrestling twenty years earlier: social exchange and trust in the absence of economic exchange and contractual agreements.In February 2022, Russia invaded Ukraine, setting in motion EU and US-led sanctions against Russia that had a widespread influence on the global economy (Åslund and Snegovaya, 2021).Companies struggled with raw material and semiconductor shortages and supply chain bottlenecks, leading to more inventory at every tier of the supply chain (Sheffi, 2022).It seems that companies are going back in time as lean practices are simply too risky.One could argue that ubiquitous discontinuities are the new normal in global supply chains (Gatenholm and Halld orsson, 2022).
There are signs that by the time the global economy returns to a new normal, businesses and their supply chains will have undergone several rounds of restructuring and reshuffling (Ho, 2020).The lessons of history will be incorporated into business processes and strategy, and consequently, taking care of "sleeping relationships" and supply chain discontinuities is suddenly of utmost importance.Thus, what are the current prospects of project marketing?Notably, numerous sequential disruptions in the marketplace after 2020, such as COVID-19, the war in Ukraine and disruptions in global supply chains, are not yet visible in the project marketing literature or in the language on discontinuity.Therefore, the outcomes of these disruptions for project marketing scholarship remain to be seen.We argue that there is a need to analyze the new ubiquitous discontinuities more granularly in terms of different project types and their temporality.Not all project businesses are alike, and there are also differences in service businesses.When these two businesses are morphed together in projects, new challenges and possibilities for project marketing emerge.We argue that project marketers should pay more attention to the different elements or content of exchange (Håkansson, 1982;Holmlund and Törnroos, 1997) in projects to understand what part of each exchange is continuing and what is discontinuing.In the following section, we provide a preliminary conceptualization for understanding discontinuity in relation to different project types.

Discontinuity and project types
There are various categorizations of different project types (Packendorff, 2002;Shenhar, 2001;Whitley, 2006), and many of these relate to the complexity and technological aspects of the project.Researchers have also provided continuums to illustrate the scope of services integrated into a project delivery (Artto et al., 2015(Artto et al., , 2008b;;Momeni and Martinsuo, 2019;Ojansivu et al., 2015).We argue that it will be useful to combine these projects and service insights into the different exchange elements in business relationships to inform a more detailed understanding of discontinuity in projects.The exchange in business relationships can be divided into four elements (Håkansson, 1982;Holmlund and Törnroos, 1997): 1 product or service exchange; 2 information exchange; 3 economic exchange; and 4 social exchange.
As shown in Figure 3, we use two dimensions: 1 project complexity and technological proprietarity; and 2 the continuum between project business and service business, to distinguish among four types of projects: sporadic projects, interlinked projects, transformative monogamy projects and transformative polyamory projects.
Each of these project types embodies specific exchange elements leading to unique discontinuity characteristics (see Figure 3).

Sporadic projects
Sporadic projects are characterized by low project complexity and technological proprietarity with minor or no service components.They involve the creation or installation of a standalone physical product or infrastructure for which ongoing support or maintenance is not needed.These can include, for example, a simple construction project, the installation of a production line, the assembly of a standard machine or the implementation of a basic IT infrastructure.
After project delivery is completed, minimum interaction is needed for sporadic projects, so all elements of the exchange are discontinuous.Furthermore, sporadic projects contain a low degree of proprietary technology (Teece, 1986;West, 2003), leaving minimal structural ties between the project buyer and seller (Holmlund and Törnroos, 1997).

Interlinked projects
When projects are more complex and include project suppliers' proprietary technology (Teece, 1986;West, 2003), it becomes much more difficult to end a business relationship after project delivery.In interlinked projects, buyers continue to purchase projects from the same seller because of their structural dependency on the latter (Holmlund and Törnroos, 1997).These projects include minimal accompanying services, which make the economic exchange discontinuous.However, information and social exchange continue during economic inactivity, as the buyer's future projects are contingent on the seller's technology.Indeed, Havila and Wilkinson (2002) illustrate that relationship energy and goodwill can be maintained even when trading stops due to existing social bonds.One example of an interlinked project includes the delivery of a sophisticated manufacturing facility where the focus is primarily on the physical infrastructure and equipment.Another example includes the delivery of an advanced research laboratory with innovative technology.The core infrastructure and equipment of such a laboratory may require only minimum or no service support beyond occasional maintenance or upgrades.To secure the compatibility between its laboratories, the buyer will need to buy its future projects from the same seller.

Transformative polyamory projects
We use the term transformative polyamory projects to describe projects that transform after project delivery into competitive service relationships that are open to several after-sales service providers.If the project relies on widely available nonproprietary technological solutions, the customer may seek to purchase after-sales services from a supplier other than the original equipment manufacturer (OEM).For example, it is common for windmills and paper machines to be serviced and maintained (onsite metrics, problem diagnostics and replacement parts) by external parties in addition to the OEMs.In these projects, economic exchange, information exchange and social exchange continue after project delivery, but the exchange is uncertain and subject to change whenever the buyer decides to switch to a competing service provider.Therefore, transformative polyamory projects include a high probability of discontinuity.

Transformative monogamy projects
Finally, transformative monogamy projects refer to projects that transform after project delivery into a lock-in type of service relationship (Grabher and Ibert, 2011).In these projects, the services are closely tied to the unique characteristics, proprietary technology or specialized knowledge associated with the original project supplier.The complex nature of the projects necessitates the involvement of the original supplier to ensure compatibility, optimal performance and effective support throughout the project lifecycle (Kujala et al., 2013).For example, projects that involve the integration of complex systems or infrastructure components, such as a smart grid or advanced transportation systems, may require services that can only be obtained from the original project supplier.The supplier possesses in-depth knowledge of the system's architecture, interfaces and intricacies, making them the most suitable provider for integration services.In these projects, economic, social and information exchange continue after project delivery, but routine service exchange is often organized through separate service organizations (Artto et al., 2015).Therefore, discontinuities in terms of internal coordination and communication between various departments and units on both sides of the business relationship can emerge (Sydow et al., 2004).Table 2 summarizes exchange elements in the different project types and the resulting discontinuity characteristics.

Discussion and conclusions
The aim of this paper was to focus on the concept of discontinuity, which is considered to be one of the most important strategic concerns in project marketing (Cova et al., 2019;Cova and Salle, 2007;Hadjikhani, 1996;Jalkala et al., 2010;Skaates et al., 2002).It could be argued that discontinuity has provided a unique identity for project marketers and a key differentiator from other B2B marketing.
Our reasoning was that by conducting a systematic literature review of the concept of "discontinuity" and by drawing on semantical, etymological and epistemological insights, we could also understand the reasons why the publications of this once burgeoning B2B research stream have plummeted in recent years.Therefore, we asked the following three questions: RQ1.How and why did the concept of discontinuity emerge in project marketing, becoming its key scholarly embodiment?
RQ2.How does the increasing use of postproject services influence discontinuity?
RQ3.What is the relevance of discontinuity for project marketers moving forward?

Summary of findings
To answer RQ (1), we need to analyze 31 years  of publishing data from major marketing and management journals.It could be argued that "discontinuity" provided a research gap that was both intellectually inspiring and managerially relevant in the project business of the 1990s.Discontinuity and sleeping relationships were conceptual innovations that proved indispensable for explaining the empirical world of project business.As Blumer (1954, p. 4) writes, "if the concept is clear as to what it refers, then sure identification of the empirical instances may be made."While this link between theory and practice remained intact, project marketers thrived.Indeed, this evolution was evident in the four chronological phases identified in the literature: the emergence of the discontinuity phenomenon (1993)(1994)(1995)(1996); the establishment of sleeping relationships as a unique embodiment of discontinuity (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006); the unfolding of the discrepancy between discontinuity and post project services (2007)(2008)(2009)(2010)(2011)(2012)(2013); and the stagnation of discontinuity research (2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023).Project marketing research peaked during the first two phases but gradually diminished as services became more prominent in project businesses.This shift made the loss of relevance more apparent.Notably, the language used to describe the discontinuity phenomenon in the first two phases differed significantly from that used in the last two phases.
To answer RQ (2), it can be concluded that contextual consideration is pertinent in understanding discontinuity.Although postproject services have become a greater focus in industrial projects, the numerous sequential disruptions in the marketplace (COVID-19, the war in Ukraine, disruptions in global supply chains) have created new ubiquitous discontinuities for projects.Consequently, there are still project types where the concept of discontinuity remains important (see Figure 3 and Table 2).
Contextual consideration and an acknowledgment of the changing project business circumstances are needed to answer RQ (3).Should the COVID-19 crisis persist over several years, project marketing could offer unique insights into managing discontinuity.However, the service business is likely to recover to where it was before the crisis.This recovery is probable because digitization and servitization appear to feed each other (Coreynen et al., 2017).At that point, project marketing would be up against a wall again.Rather than hoping for the service business to disappear and the "sleeping relationships" to return as in interlinked projects (see Figure 3 and Table 2), project marketers could investigate the best ways to manage service exchanges.Both transformative polyamory projects and transformative monogamy projects (see Figure 3 and Table 2) transition into some form of service exchange, and this is a complex organizational undertaking at the customer interface (Artto et al., 2016;Ojansivu and Alajoutsijärvi, 2015;Turkulainen et al., 2013).Presumably, there is a more complex discontinuity phenomenon to be discovered in project business beyond the original on/off economic exchange (Artto et al., 2015;Jalkala et al., 2010) as well as in society more broadly given the increasing scholarly attention to temporality (Granqvist and Gustafsson, 2016;Reinecke and Lawrence, 2022).Project marketers could have a remarkable role in: elucidating the discontinuity characteristics of different project types; mapping the various forms of postproject service exchange; increasing the understanding of the organizational/ contractual arrangements needed to manage the service transitions successfully; and managing the complex buyer-seller interface in the service-intensive project business and the inevitable temporalities amid temporary projects and more enduring business relationships.
In this light, there is a bright future for project marketing.

Implications for research and practice
Our study provides three contributions to project marketing research.First, we draw semantical, etymological and epistemological insights into the concept of discontinuity and capture the zeitgeist of 31 years  of project marketing research.Second, we envision future directions for project marketing research in the changing project business environment.Finally, we develop a conceptual framework elucidating what part of exchange is continuing and what is discontinuing in business relationships in the different project types.In the conceptual framework, project complexity and technological proprietarity (Teece, 1986;West, 2003) are combined with the different elements of exchange (Håkansson, 1982;Holmlund and Törnroos, 1997) to elucidate the discontinuity characteristics of the resulting business relationships (see Figure 3 and Table 2).
Our findings also make three contributions to the B2B marketing literature.First, we reveal the risks related to marketing scholars and practitioners losing sight of each other as business practices evolve much faster than scholarly research can keep up.Our conclusion is that the main reason for the stagnation of project marketing research during the fourth chronological phase (2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023) is the lack of correspondence between the empirical world of project business and the theories of project marketing that seek to explain it.The project marketing literature "case" illustrates the importance of the constructive dialog between marketing scholars and practitioners as necessary for the relevance of a strand of marketing to be sustained over time.
Second, we highlight the role of interdisciplinary collaboration in advancing conceptual innovations.Project marketers have collaborated successfully with project management (Cova and Salle, 2005;Skaates and Tikkanen, 2003) and solution-selling scholars (Cova and Salle, 2007).Perhaps project marketers could reach out to service researchers, project management and supply chain scholars to pair atypical knowledge with conventional knowledgea recipe for scientific impact and innovative ideas (Uzzi et al., 2013).As postulated previously, project marketing could have a significant role in the future as the world gradually turns into a "project society" (Lundin et al., 2015).Moreover, business relationships with Russian companies are effectively frozen, and business service exchange on hold.This provides an interesting breeding ground for project marketing, supply chain and service researchers.
Finally, our research elucidates the need for broader metatheoretical reflection to keep a research tradition on an upward trajectory.It could be argued that the lack of correspondence between the empirical world and theory can lead to an "elephant in the room" type of situation.One could argue that project marketing has suffered from an "academic drift" (Corbett and Van Wassenhove, 1993;Harwood, 2010) where the applicability of knowledge has gradually diminished as the discipline has lost touch with changing business practices.As discovered in the project marketing case, the language used to portray discontinuity became more implied, superficial and less tied to the original strategic objectives of project marketing toward the end of phase four (2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023).It is almost like scholars were carefully choosing words to avoid the foreseeable controversy.We encourage B2B marketing scholars to use metatheoretical reflection to come to terms with the strengths and limitations of the current corpus and spark new innovative research openings that are more fitting in the changing business practice.

Limitations and future research
This study has some limitations.First, project marketing is a very small research field, and, therefore, any lessons learned from this field should be treated with a grain of salt.Second, the last couple of years have been very turbulent (COVID-19, the war in Ukraine, global supply chain hiccups); therefore, any predictions of future project marketing research are only indicative.Finally, this research was limited to project marketing and its key concept of discontinuity.Other related concepts pertinent in B2B marketing, such as relationship closure, ending and termination, could have added further insights to the literature review.Future research could include these concepts and examine the connections among discontinuity, continuity, project termination and its potential restart over time.

Figure 1 Figure 2
Figure 1 An overview of the literature review

Figure 3
Figure 3 A conceptual framework to analyze discontinuity in different project types

Table 1
The concept of discontinuity in the project marketingliterature, 1993-2023

Table 2
Exchange elements in the different project types and the resulting discontinuity characteristics