Stage 1. Apply goal question metric approach to target questions.

Stage 1 of the Systematic Literature Review (SLR) protocol focused on applying the Goal Question Metric (GQM)approach proposed by Basili and Caldiera, with the aim of structuring the research process from an analytical and measurable perspective. At the conceptual level, four Search Goals (SG1–SG4) —What, How, Which, and Why— were defined to establish the motivation, scope, and justification of the study, as well as to identify trends, gaps, and existing cybersecurity models. At the operational level, these goals served as the foundation for formulating the Research Questions (RQs), which were evaluated using twelve quality criteria (clarity, relevance, consistency, feasibility, among others) to ensure methodological precision and coherence. Finally, at the quantitative level, metrics were defined for each question to enable objective measurement of responses, and seven data sources, including academic databases and gray literature (Scopus, Web of Science, IEEE Xplore, ScienceDirect, SpringerLink, ACM Digital Library, and Google Scholar), were selected following the methodological guidelines of Kitchenham and Charters (2007) and the PRISMA 2020 reporting standards. This ensured traceability, comprehensiveness, and methodological rigor throughout the development of the review.