Christian Appenzeller-Herzog

Citation tracking (CT) collects references with citation relationships to pertinent references that are already known. This scoping review maps the benefit of and the tools and terminology used for CT in health‐related systematic literature searching. We included methodological studies on evidence retrieval by CT in health‐related literature searching without restrictions on study design, language, or publication date. We searched MEDLINE/Ovid, Web of Science Core Collection, CINAHL/EBSCOhost, LLISFT/EBSCOhost, LISTA/EBSCOhost, conducted web searching via Google Scholar, backward/forward CT of included studies and pertinent reviews, and contacting of experts. Two reviewers independently assessed eligibility. Data extraction and analysis were performed by one reviewer and checked by another. We screened 11,861 references and included 47 studies published between 1985 and 2021. Most studies (96%) assessed the benefit of CT either as supplementary or primary/stand‐alone search method. Added value of CT for evidence retrieval was found by 96% of them. Science Citation Index and Social Sciences Citation Index were the most common citation indexes used. Application of multiple citation indexes in parallel, co‐citing or co‐cited references, CT iterations, or software tools was rare. CT terminology was heterogeneous and frequently ambiguous. The use of CT showed an added value in most of the identified studies; however, the benefit of CT in health‐related systematic literature searching likely depends on multiple factors that could not be assessed with certainty. Application, terminology, and reporting are heterogeneous. Based on our results, we plan a Delphi study to develop recommendations for the use and reporting of CT.

Background: Up-to-date guidance on comprehensive study identification for systematic reviews is crucial. According to current recommendations, systematic searching should combine electronic database searching with supplementary search methods. One such supplementary search method is citation tracking. It aims at collecting directly and/or indirectly cited and citing references from "seed references". Tailored and evidence-guided recommendations concerning the use of citation tracking are strongly needed. Objective: We intend to develop recommendations for the use of citation tracking in systematic literature searching for health-related topics. Our study will be guided by the following research questions: What is the benefit of citation tracking for systematic literature searching for health-related topics? Which methods, citation indexes, and other tools are used for citation tracking? What terminology is used for citation tracking methods? Methods: Our study will have two parts: a scoping review and a Delphi study. The scoping review aims at identifying methodological studies on the benefit and use of citation tracking in systematic literature searching for health-related topics with no restrictions on study design, language, and publication date. We will perform database searching in MEDLINE (Ovid), CINAHL (EBSCOhost), Web of Science Core Collection, two information science databases, web searching, and contact experts in the field. Two reviewers will independently perform study selection. We will conduct direct backward and forward citation tracking on included articles. Data from included studies will be extracted using a prespecified extraction sheet and presented in both tabular and narrative form. The results of the scoping review will inform the subsequent Delphi study through which we aim to derive consensus recommendations for the future practice and research of citation tracking.