Overcoming Current Challenges for Circular Economy Assessment Implementation in Public Sector Organisations

: Circular Economy (CE) is seen as a key strategy in achieving sustainable development and the United Nations Sustainable Development Goals (SDGs). To seize the potential of CE, public and private organisations need to evaluate and communicate their progress moving away from the non-sustainable paradigm of “take–make–dispose” towards circularity. The literature and practitioners demonstrate a growing interest in CE assessment as a driver for this transition. Nevertheless, the majority of CE assessments are implemented in private companies and implementation in public sector organisations is low. This article presents the challenges that currently prevent public sector organisations from implementing CE assessment and derives strategies to overcome them. A total of 21 CE and assessment experts from the Portuguese public sector were interviewed, and the results were triangulated with an extensive policy document review. The ﬁndings show that cultural barriers, particularly a lack of public and political pressure as well as a resistance towards change, are considered the main challenges for CE assessment implementation. Cultural challenges drive structural ones such as a lack of leadership commitment, the voluntary nature, and a missing clear governance for CE assessment. Technical and ﬁnancial challenges, contrary to previous ﬁndings of the literature, are not prioritised and are seen as a result of the cultural and structural challenges. Overall, the research suggests that CE assessment is often a discussion among academics and highly specialised practitioners. In order to drive its implementation, the debate has to involve stakeholders beyond expert circles to trigger awareness for its necessity and to facilitate usage for a broader audience.


Introduction
Circular economy (CE) assessment is gaining increasing attention as a method to drive the transition from the non-sustainable paradigm of "take-make-dispose" towards the cyclical use of resources and growth of in-use stocks, possibly contributing to sustainable development [1]. It is seen as one key strategy to a more sustainable paradigm and in achieving the United Nations Sustainable Development Goals (SDGs) [2]. According to the United Nations, CE particularly influences several SDGs, namely 6 on energy, 8 on economic growth, 11 on sustainable cities, 12 on sustainable consumption and production, 13 on climate change, 14 on oceans, and 15 on life on land [3]. In the desired shift towards the CE, evaluating the circularity of materials, products, services, and strategies or their contribution to the CE is crucial for designing and prioritizing circular solutions based on evidence [4]. Therefore, a wide range of CE assessment approaches has been developed in recent years.

Theoretical Framing of Factors Influencing CE Assessment Implementation
Successfully implementing CE assessment in a public sector organisation requires the availability of an adequate CE assessment approach [16]. It further needs the setup of a formal and comprehensive assessment process that is compatible with existing assessment approaches within the organisation [37]. Furthermore, resources, such as a budget and human resources, should be provided to ensure the planning, development, implementation, and execution of the CE assessment [38]. In addition, an organisational governance structure that fosters the implementation of a CE assessment is needed, e.g., leadership committed to the implementation of CE assessment [34]. Lastly, a cultural acceptance is required, e.g., the individuals at all levels of the organisations must understand the value of a CE assessment [39].
The CE assessment literature has not explicitly explored the challenges and drivers of CE assessment implementation yet. Existing contributions mainly detail technical implementation challenges and drivers related to the assessment approach. The debate can be summarized in two main technical sub-challenges. First, it is difficult for organisations to select an adequate CE assessment approach [10]. Due to the lack of a commonly accepted CE definition, there is no agreement about what aspects of the CE transition process and effects need to be measured [16]. The large number of existing CE assessment approaches are often criticised for ignoring context-and sector-specific factors of the CE, e.g., the impact of a given CE practice potentially leads to different results in different contexts [15]. Second, several authors highlight that using existing assessment approaches often involves complex processing of data and unclear decision management. Extensive data requirements and the resulting need for expertise are major challenges for implementation [15]. In fact, information exchange is also cited as a constraint to successful CE assessment implementation [40]. Some authors also mention the competition and rivalry among professionals with regard to their knowledge input and the employed data, indicators, models, and software which can be CE assessment implementation challenges [41].
Research on the implementation of CE strategies and practices in organisations explored further barriers. Two contributions were from de Jesus and Mendonça [42] and Kirchherr et al. [17], who aggregated previous findings and develop frameworks to conceptualise them. De Jesus and Mendonça [42] argued that four factors influence the implementation of CE: technical, economic, institutional, and cultural factors. Kirchherr et al. [17] collected empirical data from CE experts all over the EU and concretised subfactors. For example, Kirchherr et al. [17], and Plá-Julan and Guevara [43] detailed factors by highlighting, e.g., high upfront investment costs, the time-consuming efforts of performing these activities, and the need for specialised human resources as some of the most important challenges for the implementation of CE practices.
Within the literature on assessment in public sector organisations, a number of authors have discussed the obstacles to assessment [44][45][46], the experiences with assessment [47][48][49][50][51][52], or methods for promoting continuous organisational improvement through assessment [38,[53][54][55]. This research is particularly embedded in the significant body of literature on sustainability assessment in public sector organisations [56][57][58][59][60]. Contributions by Lancer Julnes and Holzer [38] and by Holzer et al. [39] detailed the importance of the distinct bureaucratic organisational structure influencing assessment implementation. For example, the absence of mandatory requirements for assessment is identified as a key challenge for implementation [56]. The lack of dedicated financial resources, for example, to hire dedicated and knowledgeable staff and to set up user-friendly Information Technology (IT) support systems is highlighted as an implementation challenge [39]. Kroll [61] demonstrated that the lack of leadership is often associated with the use of performance information. Furthermore, missing stakeholder engagement was mentioned in contributions on sustainability assessment in public sector organisations [27,62].
Besides the distinct organisational structure, public sector organisations act in a political context and are thus influenced by a political culture. Kirchherr et al. [17] identified cultural factors as the key influencers of CE implementation, including assessment practices. The particular organisational culture of public sector organisations can lead to a particular mindset of the stakeholders, e.g., an aversion to change, the emphasis of elections influencing decision making, less tolerance for well-conceived failure, little value of exploring new opportunities, and a lack of rewards for innovation [63]. Furthermore, the literature identified the absence of awareness for the necessity of assessment as a key influence factor for implementation [27].
In summary, two important remarks are presented. First, typically, there are multiple possible interaction and determination effects between the challenges as pointed out by authors such as Kirchherr et al. [17], or de Jesus and Mendonça [42]. For example, the selection of a complex CE assessment method often leads to a data-intensive and difficult CE assessment execution [16]. Another example would be that the lack of CE awareness may lead to a low interest of leadership and stakeholders for CE assessment implementation. Second, it was observed that the presented challenges can have two directions. The literature shows that the outlined challenges can prevent assessment implementation but can also drive it depending on the context. For example, leadership is presented as an implementation driver if it supports assessment [27,49] or as a challenge if leadership advocates against it [64]. The interactions among the four challenges/drivers can, thus, result in a chain reaction towards CE assessment implementation failure or success. Therefore, this article initially conducts a detailed analysis of the current challenges for assessment implementation and their most important causes. Once these challenges are identified, it is possible to derive strategies aimed at creating a cascading reaction geared towards successful CE assessment implementation.

Case Selection
Similar to the concept of CE, there is no commonly accepted definition of public sector organisations or public administration [65]. In this research organisations, ministries and agencies at the national level that clearly belong to the core government are included [66]. Our aim for this study is to gain in-depth knowledge of CE assessment implementation via the single case of Portuguese central public sector organisations. The authors suggest that single case studies can produce valid research outcomes when the case in question is illustrative for the research purpose [67]. Therefore, Portuguese public sector organisations were selected based on a combination of purposeful and convenience sampling [68]. The mix ensured the selection of an illustrative case based on purposefully selected criteria as well as context knowledge and access to the CE policy-making elite in Portugal, which was the target group for the interviews [69]. Potential impacts of the convenience sampling on generalizability of the data are acknowledged and mitigated with the purposefully selected criteria [70].
Portuguese public sector organisations were selected based on three criteria: • Portuguese public sector organisations are committed to the CE and are a frontrunner in the EU with their action plan for CE in Portugal 2017-2020 as an all-encompassing CE strategy; • They have assessment expertise. On the micro level, they assess a variety of objects, including some of their efforts in the field of sustainability [71]. On the macro level, they assess the outputs and outcomes of the CE action plan with a clear set of assessment targets [72]; • Portuguese public sector organisations do not assess their CE progress at the organisational level yet. Therefore, they can provide first-hand insights to existing implementation challenges.
In addition, Portuguese public sector organisations were chosen out of convenience as some authors of this paper were familiar with the Portuguese public administration and the existing CE and sustainability assessments as they have been working together in other research projects.

Methods
To analyse why CE assessment is not yet implemented in public sector organisations, a data triangulation approach was conducted including primary and secondary data [73][74][75]. It entailed three components: desk research, semi-structured interviews, and a policy document analysis [76]. Based on desk research, an initial coding framework regarding factors influencing CE assessment implementation in public sector organisations was developed (see Table 1). The findings from semi-structured interviews were triangulated with findings from a policy document review and coded using the framework. The desk research was conducted via Elsevier's Scopus and Thompson Reuters' Web of Science [76]. The search focused on journal articles and book chapters with no limit regarding the time of publication. Two searches were executed including the "title", "abstract", and "keywords": the first search aimed at identifying articles on CE strategy, practice, and assessment implementation in organisations (descriptors: circular economy, organisation (and synonyms, e.g., "micro"), assessment (and synonyms, e.g., "measurement" and "evaluation"), challenges (and synonyms, e.g., "barrier" or "obstacle"), and drivers (and synonyms, e.g., "facilitator"); the second search targeted assessment implementation in public sector organisations (descriptors: public sector (and synonyms, e.g., "public administration" or "public organisation"), assessment (and synonyms, e.g., "measurement" and "evaluation"), challenge (and synonyms, e.g., "barrier" or "obstacle"), and drivers (and synonyms, e.g., "facilitator"). The titles and abstracts of the identified articles were screened, and the ones that seemed most relevant to this research were included. Included articles were: • contributions on challenges and drivers of CE assessment implementation in organisations; • contributions on challenges and drivers of CE strategy and practice implementation in organisations, and • contributions on challenges and drivers of assessment implementation in public sector organisations.
Key contributions were, for example, de Jesus and Mendonça [42] exploring and categorising CE implementation barriers and drivers, Kristensen et al. [16] reviewing CE assessment approaches at the micro level, Domingues et al. [27] analysing sustainability reporting in public sector organisations, and Holzer et al. [39] analysing barriers for assessment in public sector organisations. We also examined bibliographies of the identified studies to identify further relevant literature. Overall, 158 contributions were selected. Based on the selected articles, recurring and prominent challenges were identified and selected [77]. The main findings are summarised in Table 1.  [39] (p. 24); "Subject to political wills and power struggles" [39] (p. 6); "Influenced more by the political climate" [64] (p. 536); "CE is associated with poverty" [43] (p. 73); "lack of awareness" [15] (p. 554) To collect primary data, the main method was semi-structured interviews. All interviews were carried out in English between 2019 and 2020. They were conducted in person and lasted between 45 and 90 min. An exemplary script can be found in Table A1. A total of 21 interviewees were selected in a two-stage sampling process (see Table 2). First, the Ministry of the Environment and Climate Action initially nominated participants based on CE expertise and knowledge in the field of assessment in public sector organisations. Second, snowball sampling was utilized [81]. This involved asking each interviewee to suggest further participants with the mentioned selection criteria. All interviews were recorded and subsequently transcribed [82]. The research suggests that it is possible to reach thematic saturation after 12-16 interviews [83,84].  Member of an environmental lab engaged with the implementation of environmental standards (e.g., ISO) and regulations (e.g., EMAS) 5 Expert on materials and waste streams 6 Expert on CE and eco-innovation 7 Expert for GPP strategies 8 Expert on strategic planning in the field of agriculture, forestry, and rural development 9 Expert on CE and food waste 10 Expert on the environment and defence 11 Expert on CE policies 12 Expert for environmental statistics and planning 13 Expert on environmental planning and strategies 14 Expert on CE and health 15 Expert on CE and macroeconomic implications 16 Expert on CE and macroeconomic implications 17 Expert on economic strategies 18 Expert on environmental management of the sea and ports 19 Expert on CE statistics 20 Expert on CE statistics 21 Expert on CE statistics The roles of the interviewees have been separated from their organisational belonging to ensure anonymity (see Table 3). We argue that this approach helped us gain more trust and to obtain additional insights [69]. The selected details regarding interviewees are provided whenever possible. To triangulate the empirical data from the interviews with another source existing governmental CE and sustainability assessment initiatives, reports and legislative documents in Portugal were included in the analysis. An online search as well as asking the interviewees yielded 36 relevant results, e.g., the Portuguese "Paper and Plastics Resolution" [85], introducing the mandatory assessment of resources such as paper in Portuguese public sector organisations. An overview of all selected documents, a short description and the access link (if publicly accessible) can be found in Table A2. Including this complementary source of information provided valuable insights and examples of problematic and successful implementations of CE and assessment initiatives that happened in the past. The number of included data was determined based on thematic saturation. Data collection terminated when the data produced no novel information on key research themes [86].
The empirical data was analysed in a qualitative content analysis supported by the qualitative data analysis software tool NVivo [87,88]. Following a similar approach to the study conducted by Micheli and Pavlov [89], the data were analysed through a structured coding procedure (see Table 1). The results obtained were then reviewed and critically explored. It was possible to identify, code, and categorize consistent patterns in the data. Conclusions were drawn based on the literature and the empirical data. The challenges were ranked according to their importance (high, medium, and little) [90]. Challenges with high importance were those most frequently mentioned and emphasized by many interviewees (e.g., "This is one of the most important points."; "This is very important.") as well as confirmed by the policy document analysis. Challenges with medium or little importance were less frequently mentioned and/or less emphasized (e.g., "This does not have so much power."; "It is not that."). In line with this, out of the many complex interactions between the challenges, the most important causes have been identified based on frequent highlighting by the interviewees. Departing from this, it is possible to derive strategies aimed at triggering a chain reaction for a successful CE assessment implementation. The chain reactions were identified based on existing examples and repeated emphasis in the interviews and from the policy documents.

Results and Discussion
The findings of the CE assessment implementation challenges and their most emphasized interactions are presented in sequence of their relevance, as identified in the interviews and policy documents. Figure 1 shows that important challenges for CE assessment implementation are spread across all four factors. Cultural challenges as well as challenges resulting from the bureaucratic structure cause financial and technical challenges and, therefore, have led to a missing implementation of CE assessment in public sector organisations. The findings of the CE assessment implementation challenges and their most emphasized interactions are presented in sequence of their relevance, as identified in the interviews and policy documents. Figure 1 shows that important challenges for CE assessment implementation are spread across all four factors. Cultural challenges as well as challenges resulting from the bureaucratic structure cause financial and technical challenges and, therefore, have led to a missing implementation of CE assessment in public sector organisations.

Cultural Challenges
The empirical data confirms that there is a lack of awareness for the necessity of CE assessment in Portuguese public sector organisations, which is considered a root cause for the absence of its implementation. The policy documents showed that current assessments that could be associated with CE, such as the measurement of paper and plastics consumption, are not explicitly mentioning CE [85]. According to the data, two reasons mainly lead to this absence. First, there is no public and political pressure pushing the topic of organisational CE assessment onto the agenda of decision makers (interviewees # 6, 8-10, 12, 13, 15, 16, and 19-21). One interviewee highlighted: "I think the main problem is that CE assessment is not a priority at the moment.
[…] still the political level and the public opinion is not aware" (interviewee # 8). Second, there is a lack of role models and peers who already included CE assessment in their internal operations and strategies (interviewees # 1, 7, 12, and [18][19][20][21]. For example, the EU included CE assessment of public organisations neither in their Circular Economy Action Plan of 2015 nor in the New Circular Economy Action Plan for a Cleaner and More Competitive Europe as part of the Green Deal from 2020 [91,92]. An interviewee mentioned: "we take part in several groups at the European Union, World Bank, OECD and when we share our experience, we always try to share what we have been doing, share the challenges we are facing and trying to see  The empirical data confirms that there is a lack of awareness for the necessity of CE assessment in Portuguese public sector organisations, which is considered a root cause for the absence of its implementation. The policy documents showed that current assessments that could be associated with CE, such as the measurement of paper and plastics consumption, are not explicitly mentioning CE [85]. According to the data, two reasons mainly lead to this absence. First, there is no public and political pressure pushing the topic of organisational CE assessment onto the agenda of decision makers (interviewees # 6, 8-10, 12, 13, 15, 16, and 19-21). One interviewee highlighted: "I think the main problem is that CE assessment is not a priority at the moment. [ . . . ] still the political level and the public opinion is not aware" (interviewee # 8). Second, there is a lack of role models and peers who already included CE assessment in their internal operations and strategies (interviewees # 1, 7, 12, and [18][19][20][21]. For example, the EU included CE assessment of public organisations neither in their Circular Economy Action Plan of 2015 nor in the New Circular Economy Action Plan for a Cleaner and More Competitive Europe as part of the Green Deal from 2020 [91,92]. An interviewee mentioned: "we take part in several groups at the European Union, World Bank, OECD and when we share our experience, we always try to share what we have been doing, share the challenges we are facing and trying to see how other countries are working". He added that they are usually following international instructions, but in the case of CE, they do not exist (interviewee # 19).
In addition, the bureaucratic mindset within the organisation and the resulting resistance towards change led to a perception that CE assessment creates more work than benefits. Especially in the context of some existing sustainability assessment efforts, the interviewees argued that CE is often perceived as another new fashion trend around sustainable development which will soon be replaced by a new concept (interviewees # 7, 8, and 15-20). Regarding efforts towards sustainable development in Portugal, such a shift of concepts has occurred before. The policy document analysis showed that, in 2014, a former government developed and adopted a Green Growth Strategy in Portugal [93]. When the new government came into power, they shifted their focus on CE and launched the Action Plan for the Circular Economy in Portugal: 2017-2020 (CE action plan), replacing the former strategy [72].
Some interviewees mentioned that the organisations often perceive themselves as a service provider or legislator rather than a role model to reduce their own socioeconomic and environmental impacts (interviewees # 8, 9, and 15). An interviewee emphasized: "we are specialists in making others more sustainable but not ourselves" (interviewee # 8). The Portuguese Environmental Agency, for example, certifies organisations with the EMAS regulation. However, the policy documents show that they are themselves not a certified organisation [94]. Furthermore, it should be remembered that assessment in public sector organisations is not apolitical [78]. Some interviewees mentioned a fear of failure culture (interviewees # 12 and 13). Interviewees described widespread CE assessment and reporting as potentially making the weaknesses of public sector organisations transparent, including problems collecting the necessary data or negative CE performance results. They argued that, in some areas such as energy and paper consumption, data is collected and evaluated but the results are only communicated to a very small audience (interviewees # 11, 20, and 21).

Structural Challenges
Driven by culture, the rigid and formal structure of public sector organisations support more implementation challenges. As highlighted, public sector organisations are hierarchical. Thus, successful decision making requires leadership commitment, e.g., by the ministers or secretaries of state [95]. In the Portuguese public sector organisations, there is a lack of top-level commitment promoting CE assessment (interviewees # 10-13 and 21). An interviewee highlighted: "If it was a priority, we would do it. It is a top-down process and not bottom up ( . . . ) A mandate from the Ministry of Finance for example. If the Ministry of Finance said that everyone has to implement CE assessment, everyone would do it or the Prime Minister. If the Prime Minister said it needs to be done . . . I think it would only need that" (interviewee # 11). Hereby, the Ministry of Finance, the Council of Ministers, as well as the Prime Minister himself were highlighted as potential driving forces.
In line with the literature, almost all interviewees emphasised the voluntary nature of CE assessment (interviewees # 5, 8, 9, 12, 13, 18, and 19). Bureaucracies often work based on strict chains of command [21]. Thus, the identified absence of obligation for CE assessment is a key challenge. Furthermore, it leads to a lack of clear objectives and targets. The policy document analysis highlighted that neither the European Union nor the Portuguese Council of Ministers passed a resolution that mandates Portuguese public sector organisations to implement CE assessment. It was argued that: "it is not a law, not obliged, not a priority for the government; so we do not do it." (interviewee # 12). The missing obligation also leads to a lack of a clear and mutually agreed plan for CE assessment.
In addition, the responsibility for CE assessment as a cross-cutting topic is not clearly defined, which challenges successful CE assessment implementation. Due to their bureaucratic structure, Portuguese public sector organisations have varying but clearly defined responsibilities, tasks, and interests. For example, the Ministry of Defence mainly protects the country sovereignty or defends its interests abroad and the Ministry of Environment works on topics such as preventing climate change or ensuring biodiversity [96]. The different tasks and responsibilities lead to several barriers for CE assessment implementation, and the commitment level varies among organisations. In the Ministry of the Environment or the Ministry of the Economy, the topic of CE and the importance of CE assessment are more widely acknowledged than in the Ministry of National Defence. An interviewee argued "it is just not seen as a priority in the military because it is not the core business of the organisation" (interviewee # 10). In addition, public sector organisations regularly change their organisational layout, which leads to a shift in tasks and responsibilities. For example, the Portuguese Environmental Agency (APA) includes multiple organisations that were recently merged, or the Ministry of Environment and Climate Action used to be the Ministry of Environment and Energy Transition until 2020 and before the Ministry for Environment and Spatial Planning until 2011. The lack of clear responsibility for a cross-cutting topic such as CE is considered a main implementation challenge.
The empirical data shows that the organisational culture, including the absence of CE awareness, as well as the structure, with a lack of CE leadership commitment and its voluntary nature, were considered major challenges to CE assessment implementation. The resulting aversion against CE assessment within the public sector organisations caused some of the following factors.

Financial Challenges
The lack of financial resources further challenges CE assessment implementation. Similar to many governments, in the Portuguese public sector organisations, budgets are allocated by the Ministry of Finance [97]. If there is no priority for CE assessment, a budget is not allocated. The financials of Portuguese public sector organisations mirror the lack of awareness and the missing organisational commitment towards CE assessment. The lack of finances leads to problems in setting up and executing a CE assessment across all Portuguese public sector organisations, e.g., eventual IT software licenses, standards, and data collection. One of the interviewees mentioned: "we cannot do nothing if we don't have tools" (interviewee # 19). Second, there is not enough dedicated and knowledgeable members of staff (interviewees # 1, 10, 15, and 17). One of the experts argued: "I think one important thing is the capacitation and involvement of human resources. Currently there is a lack of human resources that are aware of these topics and that have education in environment, energy . . . they don't need to be all environmental engineers, but they have to be aware and enjoy and like these topics" (interviewee # 10). During the interviews with the Ministry of the Environment or the Ministry of the Economy, a lack of experts was not mentioned. This might be due to the closeness of the organisational function to the topic, as public sector organisations usually hire subject matter experts [98].

Technical Challenges
A few interviewees emphasised the absence of an appropriate CE assessment approach as a CE implementation challenge (interviewees # 1, 12, 15, 16, and 19). In line with the reasoning of the financial challenges, interviewees argued that the lacking political will and organisational commitment are responsible for Portuguese public sector organisations not selecting and/or developing an appropriate assessment approach. Moreover, in line with the literature on CE assessment, some interviewees mentioned the complexity and overwhelming data requirements as challenges for CE assessment implementation (interviewees # 1, 2, 6, 7, 12, 15, 16, and 21). There is a large interest from academic researchers in assessing CE in organisations with fewer contributions from practice, which indicates the complexity of CE implementation [16]. The literature provides a large number of CE indicators which cover multiple CE principles and are complex to understand and to apply. An interviewee highlighted, "We need to be more aware of this and we need more statistics and data support from the national office, like Statistics Portugal" (interviewee # 7). Furthermore, existing assessment efforts show that public sector organisations do not have a working infrastructure for a CE assessment across the different public sector organisations [99,100]. For example, in the context of the questionnaire related to the paper and plastic resolution [99], the interviewees highlighted the absence of a government-wide IT infrastructure and the use of the different systems and tools as key implementation challenges. The existing IT is often not ideal to share data across organisations, and updating it would require financial resources (interviewees # 2-5, 12, 13, and 20) [99].

Strategies to Overcome Challenges in CE Assessment Implementation in Public Sector Organisations
As pictured in Figure 2

Strategies to Overcome Challenges in CE Assessment Implementation in Public Sector Organisations
As pictured in Figure 2, two triggers for two possible strategies driving CE assessment implementation were identified. The empirical data gave further insights and examples of how the two chain reactions might evolve in the given context. In the first strategy, the political mindset of decision makers triggers a chain reaction towards an increased awareness for CE assessment that leads to leadership commitment, an obligation for CE assessment, and an allocation of responsibilities and financial resources. The interviews as well as the policy document analysis show that the topic of CE will gain increased attention in Portugal in the near future, e.g., because Portugal will take over the presidency of the Council of the European Union January-June 2021, where CE will play a central role as a part of the European Green Deal [83]. In line with the literature, the interviewees suggested that this event could prompt Portuguese policy makers to take interest in gaining a CE reputation. Beyond the Portuguese context, the literature argues that having a political purpose for collecting CE assessment data may overcome the resistance to CE assessment resulting from the bureaucratic mindset within the organisation [38] (interviewees # 6, 19, and 21).
The increased awareness for CE improves leadership commitment and can lead to a legal mandate for CE assessment. In a public sector organisation, leaders clarify organisational goals and fundamentally shape the organisational culture [101]. Therefore, the buyin for CE assessment from senior managers is essential for its implementation. Moreover, the interviewees argued, in line with Holzer et al., [39], that an obligatory character of CE assessment would be a crucial driver for successful implementation: "When we are In the first strategy, the political mindset of decision makers triggers a chain reaction towards an increased awareness for CE assessment that leads to leadership commitment, an obligation for CE assessment, and an allocation of responsibilities and financial resources. The interviews as well as the policy document analysis show that the topic of CE will gain increased attention in Portugal in the near future, e.g., because Portugal will take over the presidency of the Council of the European Union January-June 2021, where CE will play a central role as a part of the European Green Deal [83]. In line with the literature, the interviewees suggested that this event could prompt Portuguese policy makers to take interest in gaining a CE reputation. Beyond the Portuguese context, the literature argues that having a political purpose for collecting CE assessment data may overcome the resistance to CE assessment resulting from the bureaucratic mindset within the organisation [38] (interviewees # 6, 19, and 21).
The increased awareness for CE improves leadership commitment and can lead to a legal mandate for CE assessment. In a public sector organisation, leaders clarify organisational goals and fundamentally shape the organisational culture [101]. Therefore, the buy-in for CE assessment from senior managers is essential for its implementation. Moreover, the interviewees argued, in line with Holzer et al. [39], that an obligatory character of CE assessment would be a crucial driver for successful implementation: "When we are obliged, we do it. 'Simplex', for example, it was binding a national policy we had to comply to. We just executed it and implemented" (interviewee # 11) [102]. They explained that a resolution from the Council of Ministers, a body that includes all senior ministers in Portugal, would be most effective (interviewees # 2 and 5). The policy document analysis confirmed this, showing that government-wide approaches were triggered by mandatory resolutions from the top level, such as Simplex, SNIERPA, and SPeM [102][103][104]. The case of Simplex further highlighted that a legal mandate can also trigger the necessary allocation of a budget for dedicated skilled staff as well as for initiating and executing CE assessment [102].
A second chain reaction is triggered by increased stakeholder engagement to select and codevelop a CE assessment approach and process (interviewees # 1, 8, and 9). Research on sustainability assessment already noticed that stakeholder engagement plays a crucial role [59]. Individuals at all levels of the organisation need to understand the value of the assessment before they can fully embrace the changes [39]. It is suggested by the literature and interviewees to include all relevant stakeholders for identifying the assessment approach and execution process [7]. The interviewees argued, "If you don't transmit, if important stakeholders are not involved, you may have the best plan for your organisation, but it will not work." (interviewee # 1). An identified best practice from the interviews was the start of assessment ideas often by developing a methodological approach proposed by sectoral experts and then by circulating it throughout the entire organisation to receive contributions. The members of staff have 10 days to contribute to the development of the assessment approach, e.g., to highlight data issues, to suggest different methods, or to add organisation-specific input (interviewees # 19 and 20).
Stakeholder engagement further allows for learning from best practices of the implementation of previous assessment approaches. Many interviewees suggested the integration of a CE assessment in existing assessment schemes or toolkits for public organisations. The policy document analysis shows that sustainability assessment has already been implemented to some extent in Portugal. For example, the Administração dos Portos de Sines e do Algarve (Port Administration of Sines and the Algarve) regularly assesses and reports their sustainability efforts using the Global Reporting Initiative (GRI) guidelines [105,106]. Furthermore, the Portuguese Environmental Agency (APA) assesses and reports on Portugal's efforts towards environmental sustainability every year through the State of the Environment Report, which could be extended to also assess organisational CE efforts [107]. In line with contributions by the British Standards Institution [108] or Kristensen and Mosgaard [16], CE assessment could be included in the existing standards, guidelines, toolkits, certification schemes, or eco labels.
According to Saidani et al. [15], about 45% of existing CE indicators are linked to computational tools, making their application and implementation more convenient for practitioners. The interviewees advocated for supporting IT tools that need to be compatible to be used in all public sector organisations. Also, here co-development was highlighted since relying on out-of-the-box software systems that come with predesigned measures can miss the nuances of a context-specific CE assessment. Furthermore, many interviewees highlighted the importance of clear governance, including responsibilities and a chain of command similar to governance of the assessment of CE best practices resulting from the Portuguese CE action plan in 2019 [72] (interviewees # 1, 11-13, and 19). The interviewees proposed the installation of a focal point in each organisation that consolidates and reports the assessment data (interviewees # 5 and 19-21). They further argued, in line with Holzer et al. [39] that regular discussion of performance information will help engrain these practices into the culture of the organisation. This process could be supported by regular meetings and clear communication channels (interviewees # 3-5 and 19-21). Finally, the use of assessment information within the decision-making process is a critical element in producing desired outcomes. According to the literature, this component characterizes the very first step towards the institutionalization of assessments [39].

Conclusions
The previous sections presented the case study of CE assessment implementation in Portuguese public sector organisations. The analysis highlights that there are still multiple challenges for CE assessment implementation across the four factors (cultural, structural, financial, and technical) that require action. We observed a lack of CE assessment awareness, missing leadership for CE assessment implementation, its voluntary nature, and the complexity of CE assessment approaches as the most pressing challenges preventing CE assessment implementation. Departing from this, two strategies were derived leading to a commitment for CE assessment as well as a codeveloped CE assessment approach and execution process. In combination, both strategies can break the barriers and can drive the CE assessment implementation in Portuguese public sector organisations. Beyond this case study, this research draws broader theoretical and practical lessons.
First, CE assessment of organisations is difficult to implement in the public sector. All interviewees involved in this research were able to mention multiple implementation challenges. As outlined in Section 2, the current research on CE assessment argues that technical challenges cause the failure of CE assessment implementation. Nevertheless, the data show that cultural and structural challenges for CE assessment outweigh the technical challenges and partly cause them. Especially the lack of awareness for the importance of CE assessment emerges as a key barrier. This shows that challenging prevailing assumptions of the literature and practice led to the discovery of a broader spectrum of CE assessment implementation challenges. Thus, it is important to look beyond the technical barriers of CE assessment and to focus on cultural and structural challenges.
Second, the results show that existing frameworks on barriers for CE strategy and practice implementation, such as the ones developed by de Jesus and Mendonça [42] or by Kirchher et al. [17], can serve as a basis for detailed analysis of single practices such as CE assessment. These frameworks were consolidated, and insights from the CE assessment literature and public sector-specific contributions were added. The newly developed, more detailed, coding framework guided this analysis (see Table 1). The findings from the data analysis show that no major amendments were made to the coding framework and that the empirical data was in line with the findings from the literature. The main contribution is, therefore, the merger of different fields of research and exploration of empirical data developing more detailed context-specific frameworks (see Figures 1 and 2). We argue that our approach might be transferable for analysing the implementation of other CE practices, e.g., business model implementation.
Third, we found that explicitly exploring the strategies and chain reactions for successful CE assessment implementation offered insights and concrete steps for action. It was argued in Section 2 that the identification of CE implementation challenges and their causes allow for the derivation of strategies for successful CE implementation. Most existing analyses focus on identifying the barriers and draw less attention to the strategies to overcome them, implying the clarity of the next steps. We found that the explicit analysis of strategies added value to the analysis. During the interviews, we asked directly how to overcome the implementation challenges. In addition, we analysed how existing assessment initiatives had been implemented in the past. Including this perspective led to the identification of sector-specific best practices of existing assessments or insights into successful governance of CE assessment, as requested by the CE assessment literature.
Lastly, it is important to highlight the limitations of this research. For example, selecting one case study has the advantage of describing this case in depth. In that sense, the derived framework is generalisable whereas particular findings may not be. Furthermore, the derived strategies to overcome CE assessment challenges have been developed in line with the empirical data but were not yet tested in Portuguese public sector organisations. Methodologically, interviews entail potential validity issues. This limitation was mitigated by triangulating the interview data with the findings from the policy document review. Future empirical research is needed.
We need to acknowledge that there is not one magical approach for CE assessment implementation in all public sector organisations around the world. Therefore, future research should explore further single case studies in the public sector to gain more indepth knowledge on CE assessment implementation challenges and strategies to overcome them. In addition, large-n studies can explore patterns across different institutional, cultural, and geographic contexts. Further exploring CE assessment implementation in the private sector can also give a more comprehensive view. In addition, many interviewees did not understand how CE assessment compliments already existing sustainability assessment approaches. The literature so far does not provide a comprehensive answer to this question. This research needs to be seen as a starting point for future research that is urgently needed to close the highlighted CE assessment implementation gap.

Data Availability Statement:
The data presented in this study are available on request from the corresponding author. The data are not publicly available to protect anonymity of the interviewees.

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Is there any kind of assessment in your organisation? Sets out the basis of environmental policy in compliance with the provisions of Articles 9 and 66 of the National Constitution. The Environmental policy aims to enforce environmental rights through the promotion of the sustainable development, supported by an adequate management of the environment.
Green Growth Commitment/Green Growth Coalition (GGC) Predecessor of the CE action plan. One of the three key ideas of the GGC is that "promoting the efficient use of resources implies optimised resource management aimed at increasing productivity and maximising the use of resources (e.g., material efficiency, energy efficiency, water efficiency, ecodesign, urban renewal)". It is implemented across sectors. It adopted EU climate goals and targets and further developed them. The GRI has published a pilot version of a public sector supplement specifically to address the reporting needs of these organisations (GRI 2005). There is an overview of Portuguese public sector organisations using the GRI.
https: //database.globalreporting.org The PERSU embodies waste management as a way to continue the material life cycle. Waste is managed as an endogenous resource, minimising its environmental impact and taking advantage of its socioeconomic value. This plan promotes the efficient use and management of primary and secondary resources, decoupling economic growth from material consumption and waste production.
The Portuguese Environment Agency (APA) prepares annual reports for monitoring this strategic plan.
https://apambiente.pt/_zdata/ Politicas/Residuos/Planeamento/ PERSU_II/Portaria_187_2007 _PERSU_II.pdf The PERH aims to strengthen measures for the prevention of medical waste, going beyond mere waste management to introducing the material life-cycle approach, with a focus on reducing the environmental impact resulting from production and waste management and on strengthening the concept of the economic value of waste. Moreover, it encourages the recovery of waste and the use of materials resulting from recovery, considering elimination as the very last option.
https://apambiente.pt/_zdata/ Politicas/Residuos/Planeamento/ PERH/PERH_2011_2016.pdf The Global Reporting Initiative (GRI) Reports in Portuguese public sector organisations GRI is a sustainability reporting guideline. The guidelines represent the reporting content that has been identified as most broadly relevant to both reporting organisations and report users.
https://www.intechopen.com/ books/digital-communicationmanagement/analysis-of-grisustainability-reports-issued-byportuguese-public-sector-entities The Report on the State of the Environment (OER) The OER allows us to draw a global picture of Portugal's current panorama on the environment in the context of its economic and social evolution.
https://rea.apambiente.pt/ Web form to identify sustainability practices It is a questionnaire including more than 200 questions developed by the Portuguese Environmental Agency that aims to identify good sustainability practices of the Portuguese central public sector organisations.
Interview data