# Industry 4.0 and Lean Six Sigma Integration: A Systematic Review of Barriers and Enablers
## 4 Review and Discussion
### Approaches Facilitating Integration  
This section discusses various ways to deal with I4.0 and LSS integration challenges. Based on the method introduced in [96], the approaches result from linking the enablers identified in Section 4.2 of this study to their corresponding barriers in Section 4.3, as shown in Figure 7. Following the convention adopted in [97], the arrows in the figure show which enabler categories have an advantageous effect on which barrier categories and the numbers on the lines correspond to the numerical identifier of each paper in Appendix A, directly or indirectly supporting such connections. Cultural suitability issues are mitigated by employee involvement, training, and a good understanding of I4.0 and LSS. Solid knowledge of both approaches allows company management to understand the potential benefits of each in operational performance [41, 66], which may increase their willingness to support the integration process. Moreover, it may help company management to understand the importance of a long-term vision when working with I4.0 and the value of employee training in the integration process. The latter, in particular, may boost empowerment and collaboration in the workforce [64], hence increasing employee involvement during the process. Furthermore, investing in staff training and good project management may reduce resistance to change during the integration process [91, 98]. Operational viability issues are mitigated by taking a strategic orientation during the integration process. This can be achieved, for example, by linking the implementation approach to the business strategy [39, 42, 72] so that strategic actions (e.g., significant changes in production processes) can be considered as part of the I4.0 and LSS integration roadmap to avoid any adverse effects on the process. Regarding the low level of experience and skills in LSS and I4.0, integration patterns that show how other companies have managed the integration process can be valuable tools to address this limitation. An example of an  
Figure 7: Connecting enablers to barriers for I4.0 and LSS integration (articles in Appendix A). integration pattern describing implementation considerations and examples of I4.0-based LSS solutions can be found in [23]. Another obvious mitigation action is investing in staff training, which can increase the administrative skill level inside the organisation and tackle the knowledge limitation [99]. Moreover, investing in staff training can help to reduce the learning curve. This barrier may also be mitigated by reducing the technical expertise required to deploy and run digital solutions [99]. Stakeholders outside the company can also help to tackle operational viability issues. For instance, regulatory norms from governments and other organisations may mitigate data-related challenges, such as misuse and confidentiality, which might affect the deployment of crucial technologies in I4.0, such as BDA [76]. Technological feasibility issues during integration can be reduced through actions aimed at building interconnected IT systems, which usually have characteristics such as flexibility and interoperability. For instance, the technology incompatibility barrier can be anticipated and avoided by building flexibility into the IT infrastructure since its conception so that it can adapt to future modifications in the working environment [78]. However, this may only sometimes be feasible in practice. In fact, as identified in [23], integrating I4.0 and LSS may require reconfiguring IT modules to share and exchange information. In this context, flexibility can be achieved, for instance, by adopting a modular reference architecture when developing I4.0-based LSS solutions. Modularity refers to the ability to break down a unit into parts that can be joined to create numerous configurations [77]. As a result, companies can more easily add new features (e.g., components) to the I4.0-based LSS solutions or combine them with other standalone digital solutions in an affordable way.