## 4 Evaluation
It was confirmed that SemDaServ is equally suitable for document-based and model-based approaches and thus fits well into the current state of the art (mostly document-based approach) and at the same time is fit for the future (model-based approach). The interview with expert 10 (cf. Table 4) focused on the formalization of domain knowledge. The discussion mainly focused on the right degree of formal specifications regarding the modeling language for explicating domain knowledge. A higher degree of detail in the specifications and language constructs of the modeling language leads to more difficult access to the modeling language and thus, in the expert's experience, to less use of the modeling language in practice. The advantage is the unambiguousness in the interpretation and thus the reusability of the explicated knowledge. A lower level of detail in the specifications (e.g., allowing free text without specific formal specifications) leads to less unambiguity, but the access barrier to the use of the modeling language is lower, which is why the circle of users increases. From the workshops as well as other expert interviews, it became clear that the SSSE requires a multidisciplinary team with a variety of different actors. Therefore, the SemDaServ approach uses as few formal specifications for information and data models as possible. Nevertheless, further SysML diagrams can be used, which accordingly also bring the advantages of the multitude of specified specifications of SysML. In the interview, the level of detail of the specifications in the information and data model was confirmed as sufficient. In addition, the conclusiveness of the sequence of the SemDaServ process steps for running through the knowledge pyramid was confirmed. The interview with expert 11 (cf. Table 4) focused on the broad applicability of the SemDaServ approach independent of the use case, role profiles of the actors, conclusiveness, and usefulness for practice. Expert 11 confirmed that the SemDaServ approach is generic enough to be used in an industry-independent manner. The role profiles described are appropriate and can already be found in practice in several companies. The version of the knowledge carrier matrix presented to expert 11 was not yet based on roles, but only noted the names of the knowledge carriers. This was changed at the suggestion of expert 11: In the SemDaServ version, in addition to the name, the knowledge carrier matrix primarily records the role and also the organization of the knowledge carrier. The conclusiveness of the approach and its usefulness for practice was confirmed. The interview with expert 12 was focused on the suitability of the SemDaServ approach for the possibility of achieving a complete specification of all data. The question was whether knowledge-driven domain experts can identify all relevant data for a smart service in early development phases without having to fall back on previous data. The interview revealed that domain experts can identify a large part of the relevant data by naming the required information content and information flows. Nevertheless, it is required to have domain experts check statistical analyses of already existing data-especially correlation analyses-in the context of SemDaServ. This enables the discovery of relevant correlations that were previously unknown to the domain experts or that were simply forgotten. By having the revealed correlations checked by the domain experts, spurious correlations can be discovered and excluded from the data specification. Based on the interview with expert 12, the sub-process step Integrate statistical analysis results (see Section 3.2.2) was therefore added to the data specification process Clarify information needs.