# A Systematic Mapping Study on the Modernization of Legacy Systems to Microservice Architecture
## 4 Results
### Evaluation Strategies and Maturity Level  
The rate of adoption of any scientific innovation (e.g., a solution to support software modernization) by third parties is directly related to the level of maturity of the innovation in question. Among the potential indicators of maturity, our investigation revealed that an understanding of the evaluation process may be a viable parameter. In other words, the use of evaluation strategies facilitates the identification of maturity, performance, and significant features. Therefore, to establish a parallel between the evaluation strategies and the maturity level of the initiatives identified in this SMS, the data gathered from RQ3 and RQ4 was utilized. Of the 43 studies, only 2 did not present any evidence of  
Figure 3: Sankey diagram for area, domain, application, and quantity. evaluation (i.e., S41 and S43). However, all studies were classified according to their respective maturity levels. The analysis of all the primary studies included in our mapping revealed the following evaluation strategies [22]:  
* Case study. This strategy enables an initiative for software modernization to be analyzed in a scenario closer to a real-world application. Thus, it is possible to identify particularities of an application domain and gather more precise, exploratory, and qualitative data. On the other hand, some studies used a \"toy example\" as a case study, which can be considered insufficient because of their lack of real-life context;
* Experiment. This strategy involves a process with a well-defined sequence of steps based on an execution protocol that enables future replications. In short, experiments are elaborated when it is intended to control the situation and manipulate behavior directly, precisely, and systematically. * Proof of concept. This strategy represents a test or demonstration that aims to define the feasibility of an initiative so that it can be explored usefully. Therefore, it can be said that when successful, this strategy represents an important step in the process of creating a truly operative prototype. In order to ascertain the maturity level of the proposed initiatives, evidence was gathered regarding their applicability scenarios. The evaluation strategies were then analyzed, and three categories were established to classify a study according to its maturity level: academic, industrial, and mixed. It is noteworthy that this taxonomy has been previously utilized in the research conducted by [7; 16]. Next, a brief description of this taxonomy is addressed:  
* Academic. Studies categorized as academic focus on a theoretical and experimental presentation of the investigated issue. Therefore, when evaluating such studies, experiments, simulations, comparisons with other algorithms, and examples of case studies are considered. * Industrial. Studies that adopt an industry-oriented approach primarily focus on operational aspects. They might not include an in-depth analysis of the adopted resource (e.g., algorithm or technique), as they mainly address the applicability in specific cases directed to industrial cases. * Mixed. This category encompasses studies that combine the benefits derived from both industrial and academic approaches. For instance, a software modernization initiative was formulated considering both academic research and practical applicability in industry. Figure 4 illustrates the relationship between the studies' evaluation strategies and their maturity level. Of the 43 studies of this mapping, only 2 presented evidence of evaluation through proof of concepts, with one being conducted in the academic scope and the other being mixed. Three studies, one of which was conducted in an academic context and two of which were mixed, provided evidence of evaluation through experiments. Finally, 36 studies, 23 of which were conducted in the academic scope, 6 in the industrial scope, and 7 in the mixed scope, were evaluated through case studies.