# Industry 4.0 and Lean Six Sigma Integration: A Systematic Review of Barriers and Enablers
## 4 Review and Discussion
### Integration Barriers
A third obstacle is the lack of awareness of the potential benefits of integration [32; 69; 76], which manifests as uncertainty regarding the economic value of this process, making it difficult to justify the integration initiative financially. **Operational viability--**Several process barriers to LSS and I4.0 integration have been mentioned in the literature. The first is the long learning curve [64; 79]. The integration process implies using technologies and concepts for which the company staff may have little knowledge and experience, thus requiring a long training period. Furthermore, barriers such as workforce instability and frequent changes in production processes [43; 89] may contribute to management's perception of this training period as costly and unworthy. The lack of process standardisation is a second component that appears to pose a challenge [12; 23]. When processes are not standardised, it is well known that they are more likely to be inaccurate and unreliable [59; 81], leading to financial waste. However, the lack of standardisation sometimes responds to the need for job flexibility and quality [92] which cannot be entirely avoided. Finally, companies' data privacy and security issues are also significant concerns [44; 89]. These issues can be seen as a downside of the expected data availability, sharing, and transparency increases resulting from implementing I4.0 [93]. **Technological feasibility--**Barriers in this category include technical aspects affecting IT systems' horizontal and vertical integration in the context of I4.0 and their cooperation with LSS tools and techniques [81; 83]. In this regard, insufficient or poorly designed IT infrastructure can be seen as the primary obstacle to this purpose [26; 32; 45; 86]. As for horizontal/vertical integration, technology incompatibility is, by far, the most recurrent issue in the related literature [94; 95]. Among the causes of this issue are the progressive adoption in manufacturing companies of IT systems from different software providers that cannot easily communicate with each other [23] and the absence of standard communication protocols between technology components [89]. Data integration appears to be a second technology barrier connected to the previous one [23; 71; 86; 87]. Given the amount and variety of information sources that may be available in the context of I4.0 (e.g., machines, products, and software), combining the data so that they can be accessed anywhere and shared is a challenge that may affect a company's ability to collaborate with supply chain partners. The third challenge comes from the massive volume of data collected by I4.0 technologies. As noted in [23], some companies using LSS face the challenge of extracting insights from large volumes of data captured from their manufacturing processes. In this context, traditional statistical techniques are limited in their capacity to analyse data [14], implying a limitation in conventional SS applications that may make integration with I4.0 technologies impractical.