Maturity model for determining digitalization levels within different product lifecycle phases

Digitization is the process of converting analog information into a digital format. In this format, the information consists of discrete data units that can be addressed, stored, processed, and managed separately with computing devices [11, 12]. The term “digitization” is also applied to refer to the digital revolution, along with “digitalization” or “digital transformation”. Thus, digitalization indicates a process of continuous change triggered by the growing usage of digital technologies [13] within the economy; this term is used throughout the present paper. Digital technologies are causing significant change along the value chain and creating strategic potential for companies and organizations. However, companies must attempt to manage the structural changes and organizational barriers that influence the positive and negative outcomes of this process [14].

Digitalization of manufacturing companies is implemented with the aim of horizontal integration through value networks, as well as vertical integration of all corporate levels [15]. This yields connected and integrated systems (information systems within and outside companies), objects (including products, devices, and machines), and people (workers, vendors, and users) within a company [16, 17]. Digitalization enables manufacturing companies to manage complex industrial processes [18] and introduces new possibilities, regarding e.g. efficiency, adaptivity and automation, thereby ensuring competitiveness and growth [19]. To achieve these goals, digital technologies must be implemented within all areas of a company [14]. Digital technologies are technologies that capture, process, transfer, and integrate analog information, e.g., data, documents, and procedures, into digital (virtual) values, which are then used in the work systems of manufacturing companies [20, 21]. Examples are augmented reality [22], radio frequency identification [23], and data management systems [24]. However, as noted above, only implementation of digital technologies with consideration of the associated transformation of existing organizational structures and processes, as well as employee participation (so-called “digitalization solutions”), yields successful digitalization of manufacturing companies and their work systems.

To avoid isolated digitalization solutions, a valid, end-to-end approach for all corresponding work systems is needed. Therefore, all lifecycle phases of a product must be considered. A product lifecycle consists of consecutive and interlinked steps [25] and begins with the product idea, followed by the design, process planning, product manufacturing, product usage and, finally, end of life (Fig. 1) [26]. To simplify matters, the product lifecycle is condensed to the four phases Development, Production, Assembly, and Aftersales phases within the project [27]. Nevertheless, it is essential to consider several phases in order to avoid isolated solutions and for a consistent digitalization.

The end-to-end approach supports exploitation of the effects of digitalization on other work systems [18]. For example, the quality assurance staff should be supported in performing test and measurement operations, as well as in responding to test results and correcting causes of incorrect measurements. This requires digital data preparation along several product lifecycle phases, such as product planning and product manufacturing.

The challenges of digitalization within the Development product lifecycle phase are, e.g., prospective determination of the production and the assembly work contents. Another challenge is engineering of smart products, i.e., cyber-physical systems (CPSs) that use and integrate Internet-based services to perform a required functionality [28].

Discrete parts are produced within the Production product lifecycle phase. The aim of (part) production is to produce individual parts for assembly or for delivery to customers [29]. The Assembly product lifecycle phase involves mounting of the individual parts to form modules or products [30]. As the tasks in the Production and Assembly phases differ, the material and information flow also differ. Therefore, it is necessary to analyze the process conditions in the first step before digitizing these product lifecycle phases [31]. Nevertheless, digitalization of the Production and Assembly product lifecycle phases can be achieved using CPSs, which are embedded systems connecting the physical environment and the virtual world [20]. Autonomous and cooperative elements and subsystems (e.g., CPSs), interconnected with each other and across the Production and Assembly phases form so-called “cyber-physical production systems (CPPSs)” [3].

The Aftersales product lifecycle phase contains services for manufactured goods and activities to support customers with goods usage, e.g., provision of predictive maintenance [32] and repair services as well as operating personnel training [33]. Digitalization expands the number and variety of aftersales activities and, also, customer contact [34]. Companies tend to offer not only a particular product, but also integrated solutions associated with the product [33], i.e., so-called “product–service systems (PSSs)” [35, 36]. They consist of technical product, complemented by different services of the product lifecycle [37]. PSSs are customer-oriented solutions that yield increased product value and, therefore, increased customer value [38].

Based on the knowledge that implementation of specific digital technologies can also influence processes within all other product lifecycle phases, tools to assess a company’s individual status with regard to digitalization must also consider all these phases to provide a comprehensive assessment. With the help of maturity models, a company’s digitalization level can be determined and described.

Maturity models have a wide range of applications [39], but all models are structured similarly. In general, a maturity model is an instrument to measure the current status of an object of investigation, e.g., a person, a company, or a behavior within a specific area [40]. It consists of four basic elements: a predefined number of maturity levels with accompanying descriptions, indicators and its characteristics, and linkages between each maturity level and the corresponding characteristics and recommended activities based on the resulting maturity level. To apply the instrument, the user must select the characteristics of each indicator that best fit his or her company. By consolidating these aspects, a maturity level can be calculated and corresponding activities can be recommended [41].

In this study, a selection of existing maturity models were identified (Table 1) and subsequently analyzed regarding their suitability in terms of set requirements (see Sect. 3.2).

The maturity model was designed to measure the current state of a company’s digital readiness on two levels: the company level and the level of the Development, Production, Assembly, and Aftersales product lifecycle phases. Differentiation of the phases is important as the digitalization of each single phase differs from those of the others. Furthermore, the maturity model aims to create results that can be used for companies of all sizes and as a benchmark across businesses [63]. Additionally, the InAsPro maturity model is intended to be compatible with other concepts developed through the InAsPro project, such as the technology map [21, 64] and the transformation concept [27].

Besides the already mentioned objectives, the content goals were also considered. The developed maturity model equally considers criteria associated with the Social, Technology, and Organization dimensions based on the Men-Technology-Organization (MTO) Model [65]. Therefore, besides technological criteria, organizational (especially “Data Management” and “Cooperation and Collaboration”) and social criteria (such as “Leadership,” “Corporate Culture,” and “Employee Development”) must be considered. Additionally, it is necessary to consider the corporate strategy, as decisions on creation or maintenance of competitive advantages [66] are made on the company level.

As the maturity model considers the company level as well as the four product lifecycle phases, companywide aspects must be incorporated in the model, as well as aspects specific to each product lifecycle phase. However, the specific aspects that can be considered in the product lifecycle phase do not apply to all companies equally. For some companies, it is only necessary to evaluate small work systems, e.g., a machine or a manufacturing line, whereas for other companies, it is appropriate to equate the work system with a product lifecycle phase. Therefore, the maturity model must consider scalable work systems.

Furthermore, from the user perspective, the InAsPro maturity model must be easy to understand and use, and yield a comprehensible result that can be generated with minimal effort. For easier assessment of existing maturity models with regard to their attainment of the named goals, the above goals were translated into model requirements and specifications for the model architecture, as shown in Fig. 2.

The reviewed maturity models (Table 1) were evaluated with regard to their fulfillment of the defined requirements (Fig. 2). The results are shown in Table 2.

To summarize, the majority of the existing maturity models consider digitalization and focus on companywide aspects, especially technological, organizational, and social ones. Furthermore, the approaches employed by these models concentrate on digitalization of manufacturing systems. Only a few models also consider the corporate strategy and further product lifecycle phases, e.g., Development or Aftersales. Additionally, none of the identified models divide the manufacturing area into production and assembly (see also, Sect. 2.2). As mentioned previously, a scalable work system must be taken as an object of investigation; however, this aspect is also neglected by the existing approaches. According to the above evaluation, none of the existing maturity models can fulfill all requirements to a satisfying extent. Consequently, a new maturity model must be developed.

For the structural design and development of the InAsPro maturity model, the methodological studies of de Briun [67], Becker [68], Akkasoglu [69], and Kübel [70] were considered. Those authors attempted to structure and simplify development of maturity models. By combining those guidelines, the development procedure for the InAsPro maturity model was defined. Figure 3 presents this procedure. First, preparation for development of the maturity model was conducted (Sects. 3.1 and 3.2). This was followed by the development (Sects. 3.4, 3.5) and application (Sect. 4) phases.

The InAsPro maturity model consists of four maturity levels: Explorer, Beginner, Intermediate, and Expert. These levels and their value ranges are shown in Fig. 4. Here, \(M{L}_{total}\) describes the total maturity level as regards digitalization of the company and is calculated by obtaining the arithmetic mean of the achieved maturity level of the four product lifecycle phases and the Corporate Level (see also Sect. 3.5). Additionally, for the Corporate Level as well as for each product lifecycle phase, every maturity level is defined with their characterizing aspects. These are, e.g., IT system design, development and manufacturing of smart products, as well as real-time data collection. This allows a detailed description of each product lifecycle phase and its individual maturity level. Hence, the user receives a comprehensive explanation of the calculated maturity level as well as the individual product lifecycle phases in which the user is interested. The four maturity levels are defined in Fig. 4 and the \(M{L}_{total}\) values allocated to each level are shown. Additionally, for each product lifecycle phase, exemplary characteristics for each maturity level are presented.

The calculation of the digitization maturity level follows the structure of the model. Not only for each product lifecycle phase and for the corporate level an individual maturity level is calculated, also for each dimension and criterion. This enables companies to compare the digitalization degree of different dimensions as well as product lifecycle phases in more detail.

Starting with the value of each criterion (e.g. IT-system design or Data management), each criterion digitization degree (\({DD}_{criterion}\)) can be calculated through the mean of the belonging indicator values (\(i{v}_{n}\)) depending on the total number of rated indicators \(N\in \left\{1, 2 ,3 ,\dots \right\}\)

If the user does not evaluate an indicator (e.g. networking along the value chain or data evaluation), this missing value is not considered within the calculation and therefore it does not change the resulting dimension maturity level (\(M{L}_{Dimension}\)). The maturity level of the dimensions Technology, Organization, Social and Strategy can be calculated through the mean of the belonging criterion digitization degree (\(D{D}_{criterion k}\)) depending on the total number of rated criteria \(K\in \left\{1, 2 ,3 ,\dots \right\}\):

For each of the product lifecycle phases Development, Production, Assembly and Aftersales as well as the corporate level, the digitization maturity levels for all dimensions are calculated. To receive the maturity level for each product lifecycle phase (\(M{L}_{plp}\)) and the Corporate level (\(M{L}_{cl}\)), the mean of the calculated dimension maturity levels is taken depending on the total number of rated dimensions\(M\in \left\{1, 2 ,3, 4\right\}\):

Finally, the total maturity level (\(M{L}_{total}\)) over all product lifecycle phases and the companywide aspects can be determined. \(M{L}_{total}\) is calculated as shown below, where \(Q\in \left\{1, 2 ,3, 4\right\}\) is the total number of rated product lifecycle phase.

According to the structure of the InAsPro-maturity model, \(M{L}_{sca}\) has to be always determined. Depending on the product lifecycle phase the user is looking at, only those phases are considered within the calculation. An application example is described in Sect. 4. Adding additional weighting factorsto the calculation is possible, but it is not recommended, as this might shift the results and will therefore hide the less digitalized areas. All product lifecycle phases should be treated equally, and the prioritization of the digitalization process depends on the company’s internal decisions.

The InAsPro maturity model is structured according to different levels of consideration: the Corporate Level and levels corresponding to the product lifecycle phases (Development, Production, Assembly, and Aftersales) (Fig. 5). The Corporate Level focuses on companywide aspects such as digital strategy, business models, and IT security, to gain an overall impression of the digitalization level of the company.

For each level of consideration, the model analyzes the Technology, Organization, and Social dimensions. On the Corporate Level, the Strategy dimension is added as a fourth dimension. Note that strategy can only be investigated on the Corporate Level because strategy (according to its definition) refers to decisions on how the company will create or maintain competitive advantages [66]. This decision can only be made at a Corporate Level. Actions performed within individual product lifecycle phases can implicitly support the strategy [71, 72] but cannot define a unique strategy [73].

Each dimension is described by criteria such as “IT-System Design” or “Customer Service” within the Technology dimension and “Corporate Culture” or “Leadership” within the Social dimension. Furthermore, the criteria depend on the level of consideration. Within the Organization and Social dimensions, all criteria for the Corporate Level are the same as those for the product lifecycle phases. Only within the Technology dimension do the criteria vary. This is because of the specific use of digital technologies with certain purposes in a given product lifecycle phase. The criteria associated with both the dimensions and the levels of consideration are shown in Fig. 5.

Indicators describe the abovementioned criteria. For example, an indicator for the Transport criterion within the Technology dimension is identification of components in a manufacturing process (Table 3). The indicators are developed iteratively within the InAsPro project and are formulated as questions. Each indicator contains four stages representing the digitalization progress of the associated criterion. They are described textually (see also supplementary material). The first stage starts with an indicator having no or low digitalization whereas the fourth stage describes a fully digitalized indicator (Fig. 6).

Within the Organization and Social dimensions, the majority of the criteria have the same name, but the indicators vary in accordance with their associated product lifecycle phase. Therefore, the indicators must be evaluated considering their context within their individual product lifecycle phases. As an example, the Leadership criterion contains the “Communication of digitalization projects” indicator, which may vary between the product lifecycle phases in response to different executives with different management styles. Furthermore, the presence of the same criteria across the product lifecycle phases and the Corporate Level allows easier comparison of the degree to which a given criterion is digitized. A selection of criteria, indicators, and stages of the InAsPro maturity model are presented in Table 3. An example of the Corporate level (IT-System Design) points out the detailed description of the maturity stage definitions and is given in Table 4. A detailed description of the full set including the stage definitions and their detailed descriptions, are presented in the attached “InAsPro maturity model guide” as well as in the software demonstrator [74].

As the InAsPro maturity model is implemented within a software demonstrator, it begins with introductory questions consisting of general questions, e.g., questions regarding the company branch that is presently active or the number of employees employed by the company (Fig. 7). The introductory questions enable categorization of the data sets regarding different sectors, countries and regions, company size, etc. Consequently, setting a benchmark between these categories is possible.

In the initial application stages of the InAsPro maturity model, the user chooses the product lifecycle phases they wish to assess. The user can choose one or all four product lifecycle phases depending on the individual objectives of the maturity assessment. Answers to the Introductory Questions and those concerning the Corporate Level are obligatory because of the structure of the maturity model (Sect. 3.5).

As an example, the developed maturity model was applied to a small and medium-sized enterprise (SME) within the mechanical engineering sector to determine its digitalization maturity level in the Development and Production product lifecycle phases. The company develops and produces its own products with high variety due to customer-specific requirements and delivers german and international markets. After applying the maturity model to the chosen product lifecycle phases, the assessment results were displayed within tables and radar charts. The results are shown separately according to the obligatory Corporate Level and the chosen product lifecycle phases. First, the result of the company’s digitalization maturity level is shown (Fig. 8). The SME has a total digitalization level of 2.0, which means it is still a Beginner in the context of digitalization. The description of this maturity level is given in Fig. 4.

For a more detailed insight, the total result was decomposed into the considered dimensions, i.e., Technology, Organization, Social, and Strategy (Fig. 9). The SME ranked on the Beginner level for all dimensions, but performed strongest in the Social dimension. For each dimension, the calculated results were presented in a radar chart containing the dimension’s criteria, e.g., IT-System Design as well as Requirement Definition, to provide more detailed identification of the strengths and weaknesses. As an example, the SME digitalization was found to be Advanced regarding the System Design & Architecture and Modeling & Simulation criteria, but the company was rated as an Explorer in the Quality Management and Production Planning & Control criteria. Therefore, there is potential for improvement in these areas. As only Development and Production were assessed for the SME, no values were given for the Customer Service and Spare Parts Logistics criteria.

In addition, the assessed digitalization maturity level was presented in terms of the processed individual product lifecycle phases, i.e., Development, Production, Assembly, and Aftersales, as well as the Corporate Level (Fig. 10). Therefore, the SME received individual digitalization maturity values for Development and Production. The assessments for all product lifecycle phases could also be examined in more detail by displaying their specific criteria. In this paper, the result for Production is used as an example (Fig. 10(2)).

The displayed graphs show well-digitized areas (values above 2.5) and areas with potential for improvement (values below 2.5). Therefore, the SME decisionmakers are provided with a basis on how to proceed. For instance, the already well-digitized areas (the pioneering strategy) of the SME can be taken as his strength the company could follow the pioneering strategies and advance his capabilities in these fields. Moreover, the less digitized areas (successor strategy) can be improved indicating a successor strategy to maintain competitiveness. Consequently, the maturity assessment results provided by the InAsPro maturity model serve as a starting point for the development of a digitalization strategy, or for questioning and adjusting an already existing digitalization strategy within a company.

Compared to existing digitalization maturity models, the developed InAsPro maturity model implements a holistic approach by considering multiple aspects of a company. That is, consideration of the Corporate Level as well as the Development, Production, Assembly, and Aftersales product lifecycle phases provides an integrated view of digitalization within the company. In particular, the crucial differentiation between the Production and Assembly heterogenous phases separates the proposed model from earlier approaches. Furthermore, the maturity model incorporates the Technology, Organization, and Social dimensions and adds Corporate Strategy to the overview. The maturity model has been developed so that work systems of different sizes can be evaluated. Thus, for example, a company can assess a workstation and, simultaneously, an entire department, in terms of digitalization.

Additionally, the maturity model facilitates comparisons between the product lifecycle phases; the acquired results can be used as a benchmark between manufacturing companies and across sectors. This aspect is ensured because the maturity model is intended to be implemented within a software demonstrator; thus, manufacturing companies can perform the assessment online. Therefore, anonymous results from different users can be compared objectively. Furthermore, differences in perception between the top management and divisional managers can be revealed, if repeatedly applied questions are answered differently on the Corporate Level and on the level of the product lifecycle phases (Sects. 3.5 and 4.1).

As technology evolves rapidly, different technologies are not explicitly considered in the maturity model and are not attributed to individual maturity levels. Furthermore, the maturity model reflects the current state and the target state is not presented. The target state is defined in the next step of the InAsPro research project using the developed concept of digitalization strategies [77]. Based on the digitalization strategies and the technology map previously reported by the authors [21], recommendations for specific application scenarios can be derived. By combining the InAsPro maturity model with the already developed technology map and digitalization strategies, a holistic modular transformation concept for work-system digitalization is developed. The concept supports companies in digitizing their work systems step by step and accompanies the implementation [2]. Furthermore, the concept was transferred into a software demonstrator, making it available for the use by the general public [74].