# Integrating Sustainable Performance into the Digital Maturity Models for SMEs in Manufacturing
## 3 Literature Review
### Sustainable Performance Measurement
#### 3.3.1 Economic Performance
[44] shows that improving OEE positively impacts competitive advantage and differentiation strategy. The findings of [46] indicate that in some cases, digitalisation significantly contributes to achieving higher productivity, resulting in reduced costs and waste or increased added value within the factory. In addition to overall equipment effectiveness, refs. [54; 59] use the **number of parts produced** per hour to measure operational efficiency. Similarly, ref. [48] mentions measuring the **percentage of worker productivity**. These indicators are factored into the OEE calculation. Regarding the efficiency of informational processes, some authors, such as [33; 60], use the **level of transparency throughout the process**, while [36; 61] use the **time to market**. Once again, using the example from [44], the authors suggest that increasing data and process transparency adds value across the three dimensions of sustainable development, thereby increasing economic performance. According to [57], reducing time to market also boosts economic benefits by enabling a project to start sooner. Thirdly, some literature associates **competitive advantage** and **customer experience level** as relevant indicators for measuring economic performance. Authors of 22 articles state that increasing competitive advantage, such as reducing lead times, fostering innovation, and improving quality, enhances customer experience, generating economic benefits for SMMEs. Ref. [50] simply uses the **level of customer satisfaction** as an indicator for measuring customer experience level. However, other authors take a more precise approach by focusing on measuring competitive advantage to determine the economic benefits of I4.0. They propose indicators such as agility level, market value creation, and multidisciplinary innovation. For measuring **personalisation and agility levels**, 14 different authors, including [31; 46], suggest that improving this indicator enhances competitive advantage, such as enabling the offering of customisable products. Findings by [31] indicate that manufacturing agility and flexibility are the most immediate opportunities I4.0 offers in terms of sustainability. Concerning **market value creation**, refs. [55; 62] and use the **level of sales increase** to measure market competitiveness [44]. Ref. [56] uses another example, namely, **multidisciplinary innovation level**, to measure economic benefits. In their article, they mention that innovation improvement indirectly helps reduce production costs. According to a small group of authors, reducing lead times also helps improve customer experience. Authors like [54; 58] use **customer delivery lead time** as an economic performance indicator. Additionally, the **time-to-market** measurement proposed by [57; 61] to measure process efficiency can also be used to gauge customer experience level. Ref. [61] also measures **design time**. Finally, several authors assert that **product quality** also impacts economic performance. According to ten authors, including [33; 34; 62; 63], quality can be used to measure customer experience and can also impact production costs. Most authors using quality as an economic indicator measure it through the **percentage improvement in quality**. More specific indicators, such as the **quantity of defective parts** and the **percentage of production errors**, are also used to support quality level measurement, including by [49; 57]. I4.0 is not solely known for positively impacting quality; for example, findings by [57] show that in some cases, quality can be negatively affected by I4.0. As mentioned, quality level can also reduce manufacturing costs, which is why, in addition to quantity indicators, ref. [48] also uses monetary indicators such as the **cost of reprocessing rejects** and the **cost of reworking** defective parts. In short, this section presents all the indicators for measuring economic performance encountered in the 28 articles of this literature review.