PRISMA 2020 and PRISMA-S: common questions on tracking records and the flow diagram

The PRISMA 2020 and PRISMA-S guidelines help systematic review teams report their reviews clearly, transparently, and with sufficient detail to enable reproducibility. PRISMA 2020, an updated version of the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) statement, is complemented by PRISMA-S, an extension to PRISMA focusing on reporting the search components of systematic reviews. Several significant changes were implemented in PRISMA 2020 and PRISMA-S when compared with the original version of PRISMA in 2009, including the recommendation to report search strategies for all databases, registries, and websites that were searched. PRISMA-S also recommends reporting the number of records identified from each information source. One of the most challenging aspects of the new guidance from both documents has been changes to the flow diagram. In this article, we review some of the common questions about using the PRISMA 2020 flow diagram and tracking records through the systematic review process.     

Development of an efficient search filter to retrieve systematic reviews from PubMed

Objective:Locating systematic reviews is essential for clinicians and researchers when creating or updating reviews and for decision-making in health care. This study aimed to develop a search filter for retrieving systematic reviews that improves upon the performance of the PubMed systematic review search filter.Methods:Search terms were identified from abstracts of reviews published in Cochrane Database of Systematic Reviews and the titles of articles indexed as systematic reviews in PubMed. Both the precision of the candidate terms and the number of systematic reviews retrieved from PubMed were evaluated after excluding the subset of articles retrieved by the PubMed systematic review filter. Terms that achieved a precision greater than 70% and relevant publication types indexed with MeSH terms were included in the filter search strategy.Results:The search strategy used in our filter added specific terms not included in PubMed''s systematic review filter and achieved a 61.3% increase in the number of retrieved articles that are potential systematic reviews. Moreover, it achieved an average precision that is likely greater than 80%.Conclusions:The developed search filter will enable users to identify more systematic reviews from PubMed than the PubMed systematic review filter with high precision.     

Preliminary comparison of the performance of the National Library of Medicine's systematic review publication type and the sensitive clinical queries filter for systematic reviews in PubMed

Objective:The National Library of Medicine (NLM) inaugurated a “publication type” concept to facilitate searches for systematic reviews (SRs). On the other hand, clinical queries (CQs) are validated search strategies designed to retrieve scientifically sound, clinically relevant original and review articles from biomedical literature databases. We compared the retrieval performance of the SR publication type (SR[pt]) against the most sensitive CQ for systematic review articles (CQrs) in PubMed.Methods:We ran date-limited searches of SR[pt] and CQrs to compare the relative yield of articles and SRs, focusing on the differences in retrieval of SRs by SR[pt] but not CQrs (SR[pt] NOT CQrs) and CQrs NOT SR[pt]. Random samples of articles retrieved in each of these comparisons were examined for SRs until a consistent pattern became evident.Results:For SR[pt] NOT CQrs, the yield was relatively low in quantity but rich in quality, with 79% of the articles being SRs. For CQrs NOT SR[pt], the yield was high in quantity but low in quality, with only 8% being SRs. For CQrs AND SR[pt], the quality was highest, with 92% being SRs.Conclusions:We found that SR[pt] had high precision and specificity for SRs but low recall (sensitivity), whereas CQrs had much higher recall. SR[pt] OR CQrs added valid SRs to the CQrs yield at low cost (i.e., added few non-SRs). For searches that are intended to be exhaustive for SRs, SR[pt] can be added to existing sensitive search filters.     

Managing and Coding References for Systematic Reviews and Scoping Reviews in EndNote

This article describes a novel approach for using EndNote to manage and code references in the conduct and reporting of systematic reviews and scoping reviews. The process is simple and easy for reviewers new to both EndNote and systematic reviews. This process allows reviewers to easily conduct and report systematic reviews in line with the internationally recognized PRISMA reporting guidelines and also facilitates the overall task of systematic or scoping review conduct and reporting from the initial search through to structuring the results, discussion, and conclusions in a rigorous, reproducible, and user-friendly manner.     

Development of a validated search filter for Ovid Embase for degenerative cervical myelopathy

Background

Degenerative cervical myelopathy (DCM) is a recently proposed umbrella term for symptomatic cervical spinal cord compression secondary to degeneration of the spine. Currently literature searching for DCM is challenged by the inconsistent uptake of the term ‘DCM’ with many overlapping keywords and numerous synonyms.

Objectives

Here, we adapt our previous Ovid medline search filter for the Ovid embase database, to support comprehensive literature searching. Both embase and medline are recommended as a minimum for systematic reviews.

Methods

References contained within embase identified in our prior study formed a ‘development gold standard’ reference database (N = 220). The search filter was adapted for embase and checked against the reference database. The filter was then validated against the ‘validation gold standard’.

Results

A direct translation was not possible, as medline indexing for DCM and the keywords search field were not available in embase . We also used the ‘focus’ function to improve precision. The resulting search filter has 100% sensitivity in testing.

Discussion and Conclusion

We have developed a validated search filter capable of retrieving DCM references in embase with high sensitivity. In the absence of consistent terminology and indexing, this will support more efficient and robust evidence synthesis in the field.     

Medical librarians' knowledge and practices in locating clinical trials for systematic reviews

Objective:In regard to locating clinical trials for a systematic review, limited information is available about how librarians locate clinical trials in biomedical databases, including (1) how much information researchers provide librarians to assist with the development of a comprehensive search strategy, (2) which tools librarians turn to for information about study design methodology, and (3) librarians'' confidence levels in their knowledge of study design methodology. A survey was developed to explore these aspects of how a medical librarian locates clinical trials when facilitating systematic reviews for researchers.Methods:In this cross-sectional study, a 21-question survey was sent to medical librarians via several email listservs during April 2020. Respondents were limited to librarians who make the decisions on search terms for systematic reviews.Results:Responses (n=120) indicated that librarians were often asked to search for various types of clinical trials. However, there was not a consistent method for creating search strategies that locate diverse types of clinical trials. Multiple methods were used for search strategy development, with hedges being the most popular method. In general, these librarians considered themselves to be confident in locating trials. Different resources were used to inform study types, including textbooks, articles, library guides and websites.Discussion:Medical librarians indicated that while they felt confident in their searching skills, they did not have a definitive source of information about the various types of clinical trials, and their responses demonstrated a clear need and desire for more information on study design methodology.     

Search is a verb: systematic review searching as invisible labor

Invisible labor is a term used by labor economists to describe work that contributes, and is often even necessary, to the economy but largely goes unrecognized and unpaid. Despite the fact that systematic review searching is a significant task for many librarians and knowledge professionals, the search process can be considered a form of invisible labor because it often goes without recognition. This occurs sometimes through not granting authorship to the librarian who performed the intellectual contribution of search development and sometimes through a devaluing of the search process by the choice of language used to describe the search. By using the term search as a passive verb or noun, authors devalue the real intellectual labor involved in searching, which includes decisions related to search terms and combinations, database selection, and other search parameters. This commentary explores the context of how searching is described through the concept of invisible labor.     

搜索引擎中的网页加权索引

如何对索引词加权是信息检索中的一个关键技术。本文针对搜索引擎检索的对象是Web页面这一特点 ,通过分析HTML标签的修饰功能 ,结合传统的tf idf加权公式 ,对网页进行加权索引。实验证明对于精确匹配 ,在查全率较低时系统的查准率有较大的提高。     

Updated generic search filters for finding studies of adverse drug effects in Ovid medline and Embase may retrieve up to 90% of relevant studies

Background

The most current objectively derived search filters for adverse drug effects are 15 years old and other strategies have not been developed and tested empirically.

Objective

To develop and validate search filters to retrieve evidence on adverse drug effects from Ovid medline and Ovid Embase.

Methods

We identified systematic reviews of adverse drug effects in Epistemonikos. From these reviews, we collated their included studies which we then randomly divided into three tests and one validation set of records. We constructed a search strategy to maximise relative recall using word frequency analysis with test set one. This search strategy was then refined using test sets two and three and validated on the final set of records.

Results

Of 107 systematic reviews which met our inclusion criteria, 1948 unique included studies were available from medline and 1980 from Embase. Generic adverse drug effects searches in medline and Embase achieved 90% and 89% relative recall, respectively. When specific adverse effects terms were added recall was improved.

Conclusion

We have derived and validated search filters that retrieve around 90% of records with adverse drug effects data in medline and Embase. The addition of specific adverse effects terms is required to achieve higher recall.     

Performance of conceptual framework elements for the retrieval of qualitative health literature: a case study

Objective:A growing volume of studies address methods for performing systematic reviews of qualitative studies. One such methodological aspect is the conceptual framework used to structure the review question and plan the search strategy for locating relevant studies. The purpose of this case study was to evaluate the retrieval potential of each element of conceptual frameworks in qualitative systematic reviews in the health sciences.Methods:The presence of elements from conceptual frameworks in publication titles, abstracts, and controlled vocabulary in CINAHL and PubMed was analyzed using a set of qualitative reviews and their included studies as a gold standard. Using a sample of 101 publications, we determined whether particular publications could be retrieved if a specific element from the conceptual framework was used in the search strategy.Results:We found that the relative recall of conceptual framework elements varied considerably, with higher recall for patient/population (99%) and research type (97%) and lower recall for intervention/phenomenon of interest (74%), outcome (79%), and context (61%).Conclusion:The use of patient/population and research type elements had high relative recall for qualitative studies. However, other elements should be used with great care due to lower relative recall.