# A Systematic Review of Cyber Range Taxonomies: Trends, Gaps, and a Proposed Taxonomy
## 2 Materials and Methods
### Selection Process  
Following PRISMA 2020 guidelines [26], we began by merging all records from our database searches, after which, duplicates were identified and removed. Titles and abstracts were then examined to ascertain eligibility, guided by the criteria established for each phase. Throughout the selection process, team members independently screened subsets of records, followed by consensus meetings to resolve discrepancies. To enhance consistency and reduce subjective bias, two custom-built tools were introduced in Phases II and III, supporting automated keyword mapping and iterative taxonomy refinement. Detailed descriptions of these tools are provided in Section 4. Where abstracts provided insufficient clarity, the research team consulted the full text to resolve uncertainties. Throughout Phase I, a standardized data extraction form was used to capture key information from each included paper, such as publication details (year, authors, venue), study design (quantitative, qualitative, or mixed methods), and explicit or implicit references to any cyber range dimensions. Particular attention was paid to whether a paper introduced new taxonomy elements or reinterpreted existing ones. Figure 2 details the Phase I identification and screening process that yielded the core corpus for our scoping review. We located a total of 242 records through bibliographic databases (2 records), DTU Findit (24 records), and Google Scholar (216 records). Prior to screening, 28 duplicates and 18 pay-walled items were removed, leaving 194 titles and abstracts for initial relevance screening. Of these, 144 were excluded, primarily for lacking an explicit cyber range focus, so 50 full texts were sought and retrieved without loss. During eligibility assessment, 33 papers were excluded because they presented neither a cyber range systematic review nor a cyber range taxonomy, reducing the pool to 17. \begin{table}
\begin{tabular}{l l l} \hline \hline
**Phase** & **Criterion** & **Description** \\ \hline \multirow{6}{*}{Phase I} & **IC1** & Papers on cyber ranges (CRs) that conducted a systematic literature review (SLR) \\  & **IC2** & Papers on CR that proposed or analyzed a taxonomy \\  & **EC1** & Publications written in languages other than English \\  & **EC2** & Papers published _before_ 2014 \\  & **EC3** & Papers inaccessible due to a paywall \\  & **EC4** & Opinion pieces, editorials, and other non-academic articles \\ \hline \multirow{6}{*}{Phase II + III} & **IC1** & Papers on CR architectures, scenarios, functions, and tools \\  & **EC1** & Publications written in languages other than English \\  & **EC2** & Papers published _before_ 2019 \\  & **EC3** & Papers inaccessible due to a paywall \\  & **EC4** & Papers that discussed testbeds _outside_ the CR context \\  & **EC5** & Opinion pieces, editorials, and other non-academic articles \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Inclusion and exclusion criteria applied during Phase I and Phase II + III screening. Backward-snowballing contributed one additional eligible study, bringing the final Phase I inclusion count to 18. Phase II deepened this understanding by mapping each newly identified study onto the baseline taxonomy, refining certain dimensions or merging overlapping concepts. Figure 3 follows the PRISMA 2020 convention and makes our Phase II screening process transparent. Two bibliographic sources--DTU Findit (159 records) and Google Scholar (196 records)--delivered the bulk of the material, while expert input and backward snowballing supplied 39 additional papers. After eliminating 91 duplicates, 36 pay-walled items and 36 records not including a taxonomy or literature review were excluded, and 196 titles and abstracts were screened. A further 14 items were removed for irrelevance at this stage, leaving 182 full texts for eligibility assessment; none failed retrieval. Of the supplementary 39 papers, 7 could not be obtained and 23 proceeded to eligibility checks.