The circular economy has become an important issue in recent years because it makes sustainable development feasible by creating value in the economy and by closing the energy and materials loops. However, since most companies continue to operate under a linear model, it is particularly important to start providing companies with tools that facilitate their shift to the circular paradigm. The main objective of this research is to establish the key elements that are necessary for assessing the level of circular economy implementation. To that end, the Delphi method is used to validate and define the key elements of three categories: circular economy fields of action, industrial symbiosis, and environmental certifications. As a result, this study identifies the key elements that assess the degree of circular economy implementation and that allows small and medium‐sized enterprises to understand where they are and what they need to do to improve their performance.

Continuous improvement (CI) is still one of the strongest ways for companies to achieve process excellence in order to survive in nowadays’ competitive environments. Yet, it is still very difficult to implement and sustain CI systems, mainly because of the difficulty in engaging people in these activities. Based on an exhaustive literature review, followed by a three-round Delphi study with Spanish experts, this paper helps to assess what the main elements are with respect to the CI system that could motivate employees’ intention to participate in CI activities. Main results show 44 elements grouped into 10 factors that could affect employees’ intention to participate. These factors were structured into a more comprehensive model following an interpretive structural modelling approach.

Purpose: The purpose of this paper is to perform a quantitative analysis of the literature in order to determine the main causes of delay in construction projects. Design/methodology/approach: A set of 47 articles from the literature were analyzed, yielding 1,057 different causes of delay. In order to analyze and compare the main causes of delay, their degree of impact was studied statistically. Next, a mention count method was used to determine the primary causes of construction project delays and through the use of Pareto diagrams, the main causes of delays in construction projects were determined. Findings: It was determined that the three main causes of construction project delay are problems that occur during execution, administrative problems and labor conflicts; together they account for almost 80 percent of the causes found in the literature. Moreover, it was deduced that problems during execution are based on unpredictable events, while administrative problems are rooted in poor cash flow management. In addition, seven sub-groups of delay causes were identified as being major due to the number of mentions detected. These were “Changes during construction,” “Poor construction management,” “Construction errors,” “Economic/Financial,” “Conflict/Relationship” and “Lack of experience.” Practical implications: This study provides a unique classification method, which was successfully validated, for the causes of construction project delay. Thanks to the classification, designers may use this information as a starting point for designing future construction projects, thereby minimizing the appearance of unforeseen events during construction. Moreover, the results of this study will help project managers be aware of the possible causes of delay that may affect their construction projects. This understanding can help them identify potential risks in the initial phases of the project and allow decisions to be made early before problems arise or the consequences of the deviations become irreparable. The results can also serve as input for the development of future management improvement methodologies that are aimed at reducing costs and ensuring that deadlines are met. Social implications: Identifying the factors and causes of the delays will allow mitigation actions to be taken in order to avoid delays, which will ultimately allow homes, schools, hospitals and other necessary infrastructure to be delivered on time or even before the planned date. Originality/value: This study provides a unique classification method that was successfully validated. Thanks to the classification, designers may use this information as a starting point for designing future construction projects, thereby minimizing unforeseen events during construction.