## 3 An Approach to Support the Systematicity Assessment
### What Is Systematicity?  
As stated above, according to [PERSON] et al. [9; 27] and [PERSON] et al. [2], a systematic review is a \"review that uses explicit, systematic methods to collate and synthesize findings of studies that address a clearly formulated question\". A systematic review, therefore, focuses on a clearly formulated research question and relies on systematic, reproducible, and explicit methods to support the identification, selection, and critical appraisal of relevant research meeting some eligibility criteria as well as the collection and analysis of data retrieved from that research. A systematic review also relies on explicit, reproducible, and systematic methods that allow reducing the potential bias that may arise when identifying, selecting, synthesizing, and summarizing studies.  
In that context, we define the systematicity of a review as the extent to which it is systematic, i.e., the extent to which a review exhibits good reporting quality. Based on the literature, we can conclude that the systematicity property is usually akin to several sub-properties, such as the completeness of the reporting, the transparency of the reporting, the trustworthiness in the review findings, the appropriateness of the methods used to conduct the review, the unbiasedness of the reporting, and the reproducibility of the study [2; 6; 8; 14; 29; 39]. Given a review that was planned, conducted, and reported using a specific reporting guideline, we can also perceive the systematicity as the extent to which systematic reviewers who authored that review have adhered with the target reporting guideline. In this regard, [PERSON] et al. [22] defined adherence as the \"Action(s) taken by authors to ensure that a research report is compliant with the items recommended by the appropriate/relevant reporting guideline. These can take place before or after the first version of the manuscript is published.\"  
Based on the literature, e.g., [PERSON] et al. [10], [PERSON] et al. [15], [PERSON] et al. [8], and [PERSON] et al. [13], [PERSON] et al. [6], focusing on reporting quality and methodological rigor, we can conclude that the notion of systematicity is usually subjective, variable from one review to another and suboptimal given that each review does not usually abide by the same standards of quality and methodological rigor. The rationale is that some systematic reviewers usually prefer to report the items of reporting guidelines that seem the most important to them and to not report the remaining ones [5]. Besides, as [PERSON] et al. [6] pointed out, conducting a systematic review usually implies making subjective decisions at various points of the review process. These decisions that are usually made by multiple systematic reviewers may hinder the reproducibility of the review if that review does not report with sufficient details how coding and screening decisions were made and how were resolved the potential disagreements that occurred between systematic reviewers involved in the review process. Relying on quantitative assessment to assess the systematicity of reviews will, therefore, foster the objective and consistent comparison of adherence to reporting guidelines across studies [23]. Besides, quantitative assessment will help decision makers to distinguish high-quality reviews from low-quality ones and therefore to avoid accepting right away the findings of a single systematic review without second-guessing their credibility [20].  
Similar to the literature, e.g., [PERSON] et al. [19; 20], and [PERSON] et al. [18], we follow in this paper a checklist-based approach and, therefore, rely on a set of eleven items, i.e., on a set of eleven questions, to quantitatively assess the systematicity of the reviews that self-identify as \"systematic reviews\". We further describe these questions below.