## 2 Research Background and Related Work  
An application of empirical research methods has been researched by many papers. [PERSON] et al. [9] present a mapping study, wherein in the majority of selected studies, the experiment is used as an empirical method. As the results show, experiments are followed by case studies, surveys, literature reviews, replication experiments, pilot studies, and simulations [9]. Furthermore, the expert judgments are not a frequently used approach within software engineering experiments. The scope of using experiments within software engineering and its sub domains has spread over the years. In a literature review provided by [PERSON] et al. [10], only one study was detected that implemented the experiment in the domain of software metrics and measurement. On the other hand, 13 years later, [PERSON] et al. [9] identified 48 studies, with 16.2%, implementing an experiment in the software quality domain. The use of experiments in software engineering started in the 1960s [3]. The authors [3] list four dimensions characterizing the context of the experiment, including students vs. professionals, opening up a challenging domain. As the literature review provided by [PERSON] et al. [10] shows, professionals were used as the experimental subjects in only 9% of studies, and on the other hand, 86.8% of studies used students. Undergraduate students are used much more frequently, whereas graduate students are used in 10.8% of studies [10]. [PERSON] et al. [10] also reported that only three studies in seven used students and professionals while measuring the differences between the groups. No research detected differences. This was also confirmed by [PERSON] et al. [4], conducting a systematic mapping study looking into the state of the art in controlled experiments with students in software engineering. As the results indicate that the majority of controlled experiments are done using student participants, 42.33% only used graduated students. In 15.95% of experiments, students received evaluation tasks, wherein the most frequently experiments researched the student's comprehension skills [4]. [PERSON] et al. [7] presented the positive and negative aspect of using students and professionals in the experiments. The professionals are more challenging to acquire than students, and when they are willing to cooperate, the sample size is usually small [7]. However, the external validity of the results is better in contrast to using students [7]. As the results show, the choice of an appropriate subject depends upon understanding the developer population portion represented by the participants [7]. As added by [PERSON] et al. [11], student samples could efficiently step-in for a specific subset of professionals. [PERSON] et al. [7] also propose a characterization scheme dividing subjects based on their experience. The experiences can be described using three dimensions: real, relevant and recent [7]. The fact that the use of the terms professionals and students may be misleading was also pointed by [PERSON] [8], who at the same time exposed the problem of using years of experiences as a metric. [PERSON] [8] lists some drawbacks when using students as an experiment's subject. As the results of the literature review show, students could not represent the professionals, namely due to a lack of experience, differences in the use of technology, learning misconceptions, and academic orientation that may not be aligned with professional practice [8]. Within the experiments, the use of expert judgment for evaluation could also be used. Expert judgment is frequently used as one of the estimation techniques within the project management [12; 13], wherein experts have specialized knowledge [14]. Expert judgment within software quality presents the use of developers' experiences for reliable evaluation [15]. [PERSON] [12] defines expert judgment as the consultation of one or more experts. [PERSON] [13] added that experts possess experiences familiar to the judging domain.