# Web-Based Serious Games and Accessibility: A Systematic Literature Review
## 3 Method Applied for Systematic Literature Review
### Screening of Documents  
Based on the guidelines of the literature review [7], the application of the inclusion and exclusion criteria is essential to filter the results. The inclusion and exclusion criteria aim to obtain relevant primary studies to answer the defined research questions. Selection discrepancies were resolved by consensus between the authors.  
Inclusion criteria: The primary study must be related to (1) the type of publication in journals, conferences, books, and book chapters on accessibility in web-based serious games published from 2000 to 2020; (2) primary peer-reviewed studies; (3) written in English language.  
Exclusion criteria: The primary study: (1) summarizes a keynote, a workshop introduction, or only an abstract; (2) duplicate articles from the same study from different sources.  
In this phase, to describe the process, we apply PRISMA [11; 12; 25], as shown in Figure 2. PRISMA applies to all types of systematic reviews and is not limited to clinical trials. PRISMA has been conceived as a tool to help improve clarity and transparency in systematic reviews. The search and selection process is placed on a flow chart; the process phases serve as a literature reviewer's guide. This process includes: (1) the databases consulted, indicating the number of documents obtained from each of them; (2) the number of documents that are duplicates; (3) the number of papers eliminated in each stage of the process and the reasons for elimination, and (4) the number of documents included in the study. Figure 3 shows the PRISMA flow diagram with the four phases of the selection process of the articles, which are described below:  
Phase 1: Identification. Here, we include the records obtained from database searches: ACM with 92 documents, IEEE Xplore with 25 articles, Scopus with 190 articles, and WOS with 169, a total of 476 articles were extracted.  
Figure 3: PRISMA flow diagram.  
Phase 2: Screening. Here, we apply the inclusion and exclusion criteria. Of the 476 articles, 201 articles were excluded because they were duplicated in different databases, 275 articles were included. Then, in the following filter, we excluded studies written in a language other than English, review studies, abstracts, workshops, and studies on topics other than accessibility in serious games; we excluded a total of 228 studies; finally, a total of 47 reviews passed to the next phase.  
Phase 3: Eligibility. Three authors conducted an in-depth review of the full text of the 47 articles that focused explicitly on primary studies on accessibility and web-based serious games; we did not exclude any full-text articles. Furthermore, we evaluate the quality of the research articles that respond to accessibility in serious games; we apply a \"quality assessment\" of the selected articles. The purpose of this quality assessment (QA) is to weigh the importance of each of the papers chosen when the results are discussed and to guide the interpretation of findings [8]. Each QA obtains a score of one for the fulfillment of each clause (1) Is web-based serious games accessibility detailed in the paper? (2) Is the method of evaluating the accessibility of web-based games specified in the article? (3) Does the article discuss the accessibility assessment results in serious web-based games? (4) Are the accessibility issues of the web-based serious games described? (5) Is the journal where the paper was published indexed in SCImago Journal Rank (SJR)? Table 2 presents a checklist of quality evaluation.  
Phase 4: Included. We recorded 47 articles full-text articles in the quantitative synthesis. Figure 3 shows that we have not added any additional records.