# Blockchain Technology and Its Potential to Benefit Public Services Provision: A Short Survey
## 4 Research Methodology  
To provide a detailed overview of blockchain's state-of-the-art in public service delivery, we employed a systematic approach to gather and analyze relevant literature. We systematically searched relevant papers from recognized databases, including Google Scholar, Scopus, and ArXiv (Cornell University Library). To enhance our search comprehensiveness, we also included sources from the social network ResearchGate. In addition to these reputable sources of research literature, we expanded our search to encompass reliable articles, press conference releases, and public statements issued by local governments. These sources often document experimentation and implementation for which scholarly articles are not available but still offer trustworthy and valuable information regarding application scenarios and trials. We employed a detailed strategy to identify relevant literature. Initially, we conducted a broad search using predefined keywords related to blockchain and public services. Each selected reference was then quickly skimmed to summarize its main content in terms of keywords, allowing us to identify common topics and themes. To ensure the inclusion of only pertinent studies, we applied specific eligibility criteria. Studies were included if they focused on blockchain applications in public services, were published in peer-reviewed journals, or represented credible sources of grey literature (e.g., government reports and press releases). We excluded sources that did not directly pertain to our research context or lacked sufficient methodological rigor. In Figure 1, we summarize our flow diagram. Following the initial selection, we reduced the number of references by eliminating those that did not meet our eligibility criteria. This refinement process significantly reduced the collection of references. To systematically categorize the information, we developed a comprehensive organizational framework. This involved arranging our sources into three distinct categories: the technological tools employed (such as smart contracts, the Metaverse, smart cities, and SSI), the geographical location of the experiments (such as Italy, Europe, and other global regions), and the specific applications addressed (including digital identity management, public records management, and social welfare processes). This structured approach allowed us to synthesize the literature effectively, providing a transparent and comprehensive understanding of how blockchain technology can be applied to public service delivery in alignment with the PRISMA 2020 guidelines [20]. To present our findings, we leverage three different \"maps\", arranging our sources in terms of technology (i.e., technological tools employed), geography (i.e., where the experiment has been carried out), and functionality (i.e., what application has been tackled). Figure 1: The supporting PRISMA flow diagram behind our survey. For what concerns the first map, we identified four main technologies: smart contracts, the Metaverse (including its enabling technologies), smart cities and self-sovereign identity (SSI). For each of these technologies, we listed the relevant sources we found: [8, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39] for the first; [12, 13, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53] for the second technology; [30, 35] for the third; [30, 32, 37, 54, 55, 56] concerning SSI.