## 6 Evaluation of the Data Quality of the Proposed Microservice with Multi-Model Polyglot Persistence  
Data quality is a key component of the quality and usefulness of information systems. The effectiveness of business processes directly depends on the quality of the data. This section provides the results of the evaluation and comparison of the ISO/IEC 25012:2008 standard quality attributes between the monolith mainframe application and microservice  
Figure 21: The automatic data validation process. Figure 22: Microservice deployment into the cloud schema. with multi-model polyglot persistence. Each quality attribute was evaluated and graded on a scale from 1 to 5 for each application. A lower value showed a lower quality and a higher value showed a higher quality. Descriptions of the used evaluation grades are provided in Table 2.  
The evaluation was conducted in a forum of domain experts and IT experts within the organization. The forum consisted of three SSI domain experts, four mainframe software engineers, and four C# software engineers. Proof-of-concept of a microservice with multi-model polyglot persistence was compared to an existing monolith mainframe application going through the list of questions for each quality attribute. There were 150 questions, 10 questions for each quality attribute. Each question had to be applied to both applications. Questionnaire were constructed in a way to make answering possible for staff with low IT knowledge levels (domain experts). For example, one of the questions to evaluate understandability is: \"_Is the data model easily understandable?_\" Experts had to choose an answer from five possible options: _strongly disagree_ (1 point), _disagree_ (2 points), _neither agree nor disagree_ (3 points), _agree_ (4 points), _strongly agree_ (5 points). [PERSON]'s W coefficient of concordance was used to assess the agreement among the experts [64]. The coefficient value was 0.76, which indicates a relatively high level of agreement between the experts. If the test statistic W was 1, then all of the survey respondents were unanimous, and each respondent has assigned the same order to the list of concerns. If W was 0, then there was no overall trend of agreement among the respondents, and their responses may be regarded as essentially random. Intermediate values of W indicate a greater or lesser degree of unanimity among the various responses. The final results of the evaluation and comparison are shown in Table 3. The final value for each quality attribute is an average of the experts' values rounded to the nearest whole number. \begin{table}
\begin{tabular}{c c} \hline \hline
**Value** & **Description** \\ \hline
1 & Lowest quality \\
2 & Low quality \\
3 & Average quality \\
4 & High quality \\
5 & Highest quality \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The description of the used evaluation grades. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Quality Attribute** & **Monolith** & **Microservice** \\ \hline Accuracy & 5 & 5 \\ Completeness & 5 & 5 \\ Consistency & 3 & 5 \\ Credibility & 5 & 5 \\ Correctness & 4 & 4 \\ Accessibility & 4 & 4 \\ Compliance & 5 & 5 \\ Confidentiality & 5 & 5 \\ Efficiency & 4 & 4 \\ Precision & 5 & 5 \\ Traceability & 5 & 5 \\ Understandability & 3 & 5 \\ Availability & 2 & 4 \\ Portability & 1 & 5 \\ Recoverability & 4 & 4 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The results of the evaluation and comparison of the ISO/IEC 25012:2008 standard quality attributes between the monolith mainframe and microservice applications. Most of the ISO/IEC 25012:2008 standard quality attributes such as accuracy, completeness, credibility, correctness, accessibility, compliance, confidentiality, efficiency, precision, traceability, and recoverability were the same for both applications, but microservice with multi-model polyglot persistence showed better results in consistency, understandability, availability, and portability. 1.