# Lean Maturity Assessment in ETO Scenario
## 1 Introduction
### ETO Lean Assessment  
The culture of companywide assessment has grown more and more popular, leading to the diffusion of quality, health, safety, and environmental management protocols. One primary goal of this growing business culture is to measure system status with respect to given criteria, and enhance the system through feedback actions [33; 34]. This paper benefitted from and contributes to the development of such culture.  
A comprehensive review on the assessment of the implementation of lean practices within an organization can be found in [35]. Remarkable work has been carried out using quantitative, qualitative, and hybrid approaches to assess lean implementation and transformation (see [36; 37; 38]). The Leanness Assessment Tool (LAT) in [36] provided theoretical implications that helped us define the idea behind our presented model. In this work, the LAT was developed based on lean research, using both quantitative and qualitative dimensions to assess lean implementation. Among other contributions, one of the most rewarding was the Lean Enterprise Transformation Maturity Model (LESAT). This model is focused on assessing the degree of maturity of an enterprise by using lean principles and practices to achieve the best value for the enterprise and its stakeholders [39; 40].  
In [41], a combination of lean and cloud manufacturing, used to provide a lean monitoring system in a i4.0 contemporary framework, was provided.  
However, despite the numerous general assessment tools and theories available in the literature on lean assessment, more research for their application to ETO scenarios is required. In particular, it seems that a practical lean assessment method suited for ETO systems is not yet available.  
The aim of this work was to propose a practical model specifically for ETO organizations. The proposed model offers various target uses (e.g., self-assessment, consulting, and third-party auditing) and can be applied at different improvement stages (e.g., identifying and prioritizing areas for improvement, benchmarking with other organizations, progress monitoring over time, and sharing organization-wide learning). The two primary ingredients on which the proposed assessment tool was built up were: the ten ETO principles stated in [30], and the ISO 9004:2018 standard for achieving sustained success self-evaluation tool [42].  
As stated in [30], the new set of principles (listed in Table 1) aimed at enabling ETO manufacturers to pursue the lean ideal, gathered insight into lean production from the 14 principles of the Toyota Way [43], the 11 lean construction principles in [44], and the 13 lean product development principles in [45].  
In Figure 3, these principles are clustered over Management, Processes, Products, and Stakeholders. It details how those principles concur on delivering value to the customer. In an ETO scenario, the customer demand triggers the system. In this framework, continuous improvement is the engine that feeds the organization, from a dynamic perspective.  
The ISO 9004 self-auditing tool is based on five levels of assessment. This tool can clearly outline a high-level overview on management systems' effectiveness in accordance with regulatory standards. It allows the review of the organization's performance against specified criteria. It can also identify current maturity levels and determine strengths and weaknesses--with respect to management--in order to facilitate sustained organizational success. A similar approach was adopted within the ETO lean principles previously defined.