# PDCA 4.0: A New Conceptual Approach for Continuous Improvement in the Industry 4.0 Paradigm
## 6 Conclusions  
Several publications regarding conceptual, empirical, and practical studies on the application of I4.0's technologies towards LM and CI were analyzed, with their findingsbeing organized according to the stages that constitute a typical CI project. It was found that the I4.0's technologies mentioned in the literature have the potential to enhance a data-driven and more intelligent approach towards CI. It was also found that a holistic and structured framework towards an approach that combines I4.0 and CI was needed, as the vast majority of the authors focus solely on single aspects that are relevant to the subject. Thus, 11 requirements for the proposed approach were established based on functionalities or needs that are identified in the literature, as well as the relevant technologies for their materialization. These requirements were then worked in order to constitute a framework for PDCA 4.0. This framework uses I4.0's technological concepts to collect production data and constitute a factory digital twin, enabling the identification of critical aspects related to the system's performance through KPI analysis and mapping. These critical aspects are then diagnosed through intelligent data analysis and visualization tools, also enabling the determination of their root causes. Countermeasures can then be tested through simulations and/or through prototypes of the product design. This framework also aids the implementation of the improvements through the prioritization of projects, as well as their actual planning, and their follow-up and standardization activities. Another key component of this framework is related to information management, in which documentation needs to exist in a digital format in order to be stored in a PDCA database, making it accessible to everyone, everywhere. In summary, the application of I4.0 to CI contributes to a faster, more transparent, and efficient data-driven process, allowing to surpass traditional barriers related to such projects.  
As future work, the authors are already implementing the PDCA 4.0 approach in industrial companies, allowing to publish and discuss the impact, pros, and cons of the proposed approach. Another direction of research is to understand how aligned PDCA is with the concept of Industry 5.0. A deep and robust understanding of what Industry 5.0 is must be carried out prior to this analysis, but one can say that PDCA 4.0 is highly centered in humans (supporting human-based decisions and enriching humans' activities) and also fosters the sustainability performance (the application of CI has a high impact on resources efficiency, people's motivation, and the improvement of working conditions).  
Conceptualization, P.P. and D.J.; methodology, P.P., D.J., J.E. and M.G.; validation, J.E. and M.G.; formal analysis, M.S., J.E and M.G.; investigation, P.P. and M.S.; resources, P.P.; data curation, J.E. and M.G.; writing--original draft preparation, M.S., J.E. and M.G.; writing--review and editing, P.P.; visualization, J.E. and M.G.; supervision, P.P.; project administration, P.P.; funding acquisition, P.P. All authors have read and agreed to the published version of the manuscript.  
This work was supported by: FCT, through IDMEC, under LAETA, project UIDB/50022/2020; the European Regional Development Fund (FEDER) through a grant of the Operational Programme for Competitivity and Internationalization of Portugal 2020 Partnership Agreement (PRODUTECH4S&C, POCI-01-0247-FEDER-046102) and (PRODUTECHSIF, POCI-01-0247-FEDER-024541).  
Not applicable.  
The authors declare no conflict of interest.