Research Findings

We divided our research findings into three sections. First, we provided the outcome of the SLR using bibliometric mapping with regard to the methodological aspects. In the second step, we analyzed the KPIs discussed in the literature. Finally, we analyzed the role of sustainability KPIs based on management experience in order to define a clear picture of the most relevant indicators to use in order to achieve a sustainable strategy.


Bibliometric Analysis

In the next step of our work, we developed a bibliometric analysis for the relevant articles. This kind of analysis is widely applied in different fields, as it examines information in articles to investigate relevant issues in quantifiable ways. In particular, we exported all the relevant publications for our research questions, and further organized them in single Excel papers. Articles were extracted by Scopus in comma-separated values (CSV) format on Excel and organized by year of publication, starting with new releases, then older ones. Specific information was disclosed and further organized in order to obtain a complete understanding of the paper to be analyzed. This phase is fundamental for data synthesis. For this reason, the sample obtained was inserted in a specific system in order to summarize in graphical form the results achieved and their main characteristics. The exported CSV files were subsequently uploaded on VOSviewer, a system able to analyze intercorrelations between papers, their abstracts, keywords, authors, and so on. In fact, VOSviewer represents scientific software for building and visualizing all existing bibliometrics networks and linkages. However, it is important to underline that the system is ability to create text mining functionality in order to visualize correlated and often recurring networks of fundamental keywords extrapolated from the overall body of academic literature, so that relevant bibliometrics interconnections can be constructed. Figure 3 shows the existing networks in terms of the most recurring keywords created by the system on the basis of the selected scientific publications. In particular, it can be seen that "sustainability", "key performance indicators", "benchmarking", and "sustainable development" were the most frequent keywords in the sample analyzed.


Figure 3. Recurring keywords.


Figure 4 shows all keywords that are individually interconnected under the form of bibliometric networks, such that each field of interest will be connected to the others. Accordingly, "sustainability" is strongly related to the terms "key performance indicators", "sustainable development", and "performance assessment". In the same way, "sustainable development" is related to "benchmarking", "decision making", "performance", and "sustainability". The relationships between "sustainability", "KPIs", "performance", and "system" represent the main areas of interest, and this connection indicates the relevant role of KPIs in evaluating and integrating sustainability in the strategies of the sample companies selected. Sustainable development plays a pivotal role, as observed by its strong interconnection with all relevant fields and keywords. Most of the papers focus on sustainable development related to company performance.

Figure 4. Co-occurring keywords.


Finally, it is also possible to see the most cited journals in the sample created by the system based on the selected scientific publications (Figure 5). In particular, the left side of Figure 5 shows journals with the most citations: the Journal of Cleaner Production (cited 81 times) and the International Journal of Productivity (cited 52 times). We can also see other journals with more citations, such as Long Range Planning (cited 48 times), International Journal of Supply Chain Management (cited 35 times), and Technological Forecasting (cited 26 times).

Figure 5. Recurring journals.



Selection of Sustainability KPIs

We analyzed all 82 papers, and for each sustainability dimension we identified a set of KPIs connected to a company's strategy in the value creation process. All authors skimmed the documents. They worked separately reading the papers and reported their main contents on a detailed table to discuss them together in a second step. The relevance of KPI systems is that they are specific strategic indicators enabling the measurement of future projects outcomes, positive or negative. They are strictly correlated with corporate goals that must be achieved, and once each organization identifies its goals, the KPI system must be defined. Accordingly, the selection of KPIs to include should be: (1) correlated with organizational strategic objectives; (2) significant and effective to represent and explain the value creation process; and (3) reliable, comprehensive, consistent, and comparable. There is no specific limit in choosing KPIs beyond the relevant ones depending on the characteristics of each company. To this end, indicators should be selected to effectively summarize the company's situation and perspective. In this context, in addition to the papers obtained, we analyzed some of the most relevant reports on the topic provided by European and international organizations (Organization for Economic Co-operation and Development (OECD), US Environmental Protection Agency (EPA), etc.) and defined for each dimension the sustainable strategic goals and a set of KPIs connected to each of them.


Environmental Performance Indicators

The environment is the core of the sustainability dimension and represents the ability to safeguard the reproducibility of natural resources and preserve fundamental functions of the environment over time; hence it encompasses the fundamental role of natural resources and their use, and the reduction of nonrenewable resources and material degradation of nature and natural processes. In order to realize the new sustainability perspective, first it is necessary to define the environmental goals to achieve according to the SDGs. The strategic objectives are fundamental, since they allow us to identify strategies and create a guideline for the entire business process. For this reason, the Organization for Economic Co-operation and Development (OECD) provides a list of indicators that are neither conclusive nor comprehensive. The OECD has always been at the forefront in the area of environmental indicators, and during the 1990s the notion increasingly gained public attention, becoming a core issue among OECD countries, which then widely employed indicators for pollution issues and natural resources and assets. More specifically, in the first group, it is possible to recognize climate change by measuring CO2 and gas emissions, the ozone layer linked to indices on the apparent consumption of ozone depleting substances (ODS), air quality by computing SOx and NOx emissions, waste generation related to concerns about its intensity, and freshwater quality. The second group includes indicators such as freshwater resources for consumption and waste, climate change, fish resources, energy resources, and biodiversity for studies about threatened species (OECD, 2008). Additionally, the Environmental Quality Index, elaborated by the United States Environmental Protection Agency, considers seven environmental components: air, land, water, life environment, geological environment, nature, and forest. For each component, a simple index has been defined with a value between 0 and 1 to differentiate between the best possible and worst possible situations. The sum, equal to 100, sequentially defines the relative importance of each component (Environmental Protection Agency, 2014). Several authors have highlighted the relevance of environmental KPIs in implementing a sustainable strategy. Based on the papers analyzed, the most relevant environmental KPIs that impact value creation are connected to the following strategic items: (1) gas emissions; (2) renewable resources; (3) resource consumption; and (4) waste. One of the most important goals to achieve is to unify energy and climate, which will guarantee safe, economically accessible, and climate-friendly energy. Fighting against climate change is, in fact, also a stimulus for employment and growth. Different sets of KPIs have been defined in the literature.


Social Performance Indicators

The second sustainability dimension analyzed here represents the capacity of providing for citizens' welfare with equal distribution among different classes. According to Guerci et al., in this dimension stakeholders play a central role. In particular, compliance-oriented strategy has the explicit aim of including organizational and social goals into individuals' decision-making system. In addition, Oshika and Saka highlighted the relevance of social indicators in the value creation process. Therefore, as for the environmental dimension, we selected strategic goals that best represent this perspective by identifying the following goals: (1) to encourage employees to accept cultural change; (2) to improve the quality of work conditions; (3) to guarantee respect for human rights; and (4) to participate in social initiatives. Researchers have discussed the fundamental role of social indicators that address social performance value. In particular, Omann and Spangenberg, in 2002, identified several social indicators associated with social resources, average time spent on voluntary activities, equal opportunities, cultural diversity, and so on. Husgafvel et al. provided empirical evidence on the value creation impact of the occupational health and safety index, social innovations rate, and social sustainability index. Johansson et al. focused on work performance indicators; Azapagic and Krajnc and Glavič focused on the employee satisfaction ratio and promotion rate. We selected all KPIs that positively impact a company's value. Figure 6 synthetizes all indicators selected, divided by strategic goals.

Figure 6. Sustainability performance indicators.


Economic Performance Indicators

Finally, the last key dimension we summarized was economic KPIs associated with sustainability issues. Particularly relevant are aspects covered at the World Summit on Sustainable Development in Johannesburg (2002), 10 years after the conference in Rio De Janeiro. It introduced for the first time the idea that economic growth is not a synonym for development, but it is fundamental to distinguish between growth and development. In fact, the summit drew attention to the fact that development must be considered a priority with respect to economic growth. Thus, three main pillars were established: social connection at the top, economic connection, and environmental connection. In this case we refer to economics as the capacity to create durable growth of the main economic indicators, to generate revenue and employment, and to sustain the population, enhancing territorial uniqueness and efficiently employing resources. For instance, Hsu et al. focused on the growth of the gross margin ratio derived from the sustainability strategy adopted. Ferreira et al. highlighted the need to consider the total costs and investments related to environmental protection. Van der Woerd explained the relevance of financial indicators connected to sustainability in order to evaluate value creation. All KPIs selected in this dimension are shown in Figure 6. Moreover, according to Martínez-Perales et al., there is a fundamental role of management system standards (ISO 9001, ISO 14001, ISO 50001, UNE 166002, and OHSAS 18001) that allow the application of sustainability issues to be certified and guarantee the high reputation of the company and respect for norms of each dimension. For example, respect for the economic dimension is guaranteed by ISO 9001 and UNE 166002, which allow the quality of financial and economic performance to be certified. At the same time, consideration of the environmental dimension is certified by ISO 14001 and ISO 50001, which allow the application of norms connected to the issues related to natural resources, environmental impact management, environmental policy management, and environmental commitment and responsibility to be guaranteed. Finally, consideration of the social dimension is guaranteed by ISO 9001, UNE 166002, and OHSAS 18001. A company's certifications have a direct influence on its performance and management. Therefore, there is a strong link between these standards and sustainability performance. To this end, the sustainability perspective needs to include all certifications that guarantee the quality and respect of sustainability dimensions. In addition, this allows the company to have a good reputation, improving relationships with and retention of clients. Since certification is given by competent external organizations, it is guaranteed that the information on management systems used is true and impartial.


Interview Results

According to the interviews, we analyzed the strategic sustainable goals, the use of sustainability KPIs, the advantages and benefits from implementing a sustainable strategy, and how to account for and integrate these aspects in the company's strategy from the practical point of view. We discussed with the managers the most relevant goals and KPIs that could allow integration of sustainability and strategy, and we created the sustainability perspective.


Sustainable Goals

We can identify five goals suggested by the interviewees to integrate the environmental dimension into the strategy. The goals most frequently identified were connected to the following aspects: (1) using renewable energy sources (25 managers, 100%); (2) reducing the use of superfluous materials (23 managers, 92%); (3) reducing greenhouse gases (22 managers, 88%); (4) integrating environmental safeguards into government policies (16 managers, 64%); and (5) adopting a sustainable and conscious lifestyle with respect to natural resources that is still effective in stimulating economic growth (16 managers, 64%). With regard to the social dimension, the goals identified by the managers were connected to the following aspects: (1) including all members of society in the development of sustainable goals (21 managers, 84%); (2) developing stakeholder relationships (18 managers, 72%); (3) participating in social initiatives (18 managers, 72%); (4) including employees in the decision process (15 managers, 60%); and (5) using social marketing policies (14 managers, 56%). Finally, economic aspects that emerged from the interviews can be summarized as follows: (1) trends of financial indicators (25 managers, 100%), (2) checks on product quality (24 managers, 96%); (3) investing in professional training in research and development and marketing and communications (20 managers, 80%); (4) the technological process (20 managers, 80%); and (5) the quality of the process (18 managers, 72%). All goals are highlighted in Figure 7.

Figure 7. Frequency distribution of key performance indicators (KPIs).


Sustainable KPI System

For each sustainability goal, we asked the interviewees to provide the most relevant indicators to consider when implementing a sustainable strategy. We considered the most frequent KPI for each strategic goal (based on the managers' answers on the first section of the questionnaire). Figure 7 shows our descriptive statistics results considering goals, frequency per goal, percentage based on total managers, KPIs, frequency per KPI, and percentage based on answers related to the goal. For example, taking into account the environmental section, all managers focused on the renewable sources rate to measure renewable energy sources. Regarding the reduction of superfluous materials, all managers who highlighted this goal (23 of 23) focused on the rate of efficient use of materials. For the third goal, reducing greenhouse gases, 18 managers (72%) considered this indicator the best solution to implement and manage this critical aspect. For the last two goals of the environmental dimension, environmental safeguards and lifestyle toward natural resources, the indicators chosen were waste reduction (64%) and use of recycled materials (64%), respectively.
In defining goals and the consequent set of indicators, maintaining strategic coherence between the elements is of fundamental importance. The strategic objectives of the three aspects of sustainability exert a reciprocal influence: for example, obtaining a good employee satisfaction level and respect for company regulations leads to improved production processes, and this will allow the achievement of objectives connected to the economic dimension (reducing costs linked to failure to comply with regulations, improving structures and production processes, increasing customer satisfaction). At the same time, achieving the environmental goals (reducing emissions in relation to production volume, increasing the ratio between energy from renewable sources and energy used for production, reducing resource consumption, reducing the environmental impact of the supply chain) is strategically linked to the economic dimension: for example, reducing emissions reduces the risk of having penalties imposed by breaking regulations, and reducing resource consumption leads to a general reduction in costs, including those related to waste. This also has positive effects on social aspects, as it allows a healthier work environment for workers, reducing the causes of illness due to work and lowering the costs associated with absenteeism and medical care.