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Systematic Reviews and Other Evidence Synthesis Types Guide

Systematic Reviews and Other Evidence Synthesis Types Guide

Glossary

background question
Asks for general knowledge about a condition, test or treatment.
benchmark articles
Relevant articles identified in the SR Team's preliminary search(es), which meet the proposed review's inclusion criteria.
bias
Systematic error or deviation from the truth, in results.
Boolean operators
Named after George Boole, a British mathematician, who expressed the relationships between sets (or groups) of things or ideas using specific connectors, i.e., AND, OR and NOT.
case-control study
Patients with a particular disease or condition (cases) are identified and "matched" with controls (patients with some other disease, the general population, etc.). Data are collected on past exposure to a possible causal agent for the disease. Observational research.
case report
Describes the medical history of a single patient. Observational research.
case-series report
Describes the medical histories of more than one patient. Observational research.
clinical practice guidelines
Statements that include recommendations intended to optimize patient care that are informed by a systematic review (SR) of evidence and assessment of the benefits and harms of clinical interventions in particular circumstances.
clinical trial
A loosely defined term generally meaning to describe a study evaluate the efficacy and effectiveness of interventions. This term encompasses study designs ranging from randomized controlled trials to uncontrolled observations of a few cases.
Cochrane Central Register of Controlled Trials
Includes details of published articles (taken from bibliographic databases – notably MEDLINE®, EMBASE and CINAHL – and other published and unpublished sources), such as the title of the article, information on where it was published (bibliographic details) and, in many cases, a summary of the article.
Cochrane Database of Systematic Reviews
Includes the full text of regularly updated evidence-based systematic reviews of the effects of healthcare prepared by The Cochrane Collaboration.
cohort study
Two (or more) groups of people are selected on the basis of differences in their exposure to a particular agent (such as a vaccine, drug or environmental toxin) and followed to see how many in each group develop a particular disease or outcome. Observational research.
comparative effectiveness research (CER)
The generation and synthesis of evidence that compares the benefits and harms of alternative methods to prevent, diagnose, treat, and monitor a clinical condition or to improve the delivery of care. The purpose of CER is to help consumers, clinicians, purchasers, and policy makers to make informed decisions that will improve health care at both the individual and population levels. Also referred to as clinical effectiveness research, evidence-based medicine, or health technology assessment.
concept
The idea of a thing.
connectors
Words, phrases, or symbols used to combine search statements, thoughts, or ideas. See BOOLEAN OPERATORS and PROXIMITY OPERATORS.
controlled vocabulary
A list of predefined terms or dictionary, usually used with databases, to describe the subject matter of database contents. It is controlled because someone organizes it and only words on that list may be assigned to the contents. See SUBJECT HEADINGS and THESAURUS.
cross-sectional study
Data are collected at a single point in time and analyzed. Observational research.
database
A file of information. Although databases are usually thought of as being electronic or machine-readable, they may also be in only printed format. A published textbook or dictionary is technically a database.
exclusion criteria
Investigator-identified characteristics that are: (a) possessed by individuals that would exclude them from participating in a study; (b) specified to exclude studies from a body of evidence.
experimental research
Involves the study of an intervention(s)/exposure(s)/factor(s) that are controlled by the researcher. The research may or may not involve randomization of the intervention(s)/exposure(s)/factor(s).
filters
Database criterion/criteria applied to search results to limit or identify specific aspects of a search, e.g., year published. See HEDGES and LIMITS.
foreground question
Can be answered from research/evidence and focuses on specific knowledge.
grey literature
Information or materials that are not published or indexed in the traditional pipeline of databases, indexes, peer-reviewed journals, and monographs, including such items as clinical trial registers, internal company reports, speeches, and posters presented at meetings.
hedges
Sets of related words (natural language, subject descriptors, or both) describing a concept and used as one of the search's building blocks or as a filter for the search results. See FILTERS and LIMITS.
keyword
Individual word searchable in any field of a record. See NATURAL LANGUAGE.
index term
See CONTROLLED VOCABULARY, SUBJECT HEADINGS, and THESAURUS.
inclusion criteria
Essential characteristics specified by the investigator that: (a) potential participants must possess to be considered for a study: (b) studies must meet to be included in the body of evidence.
integrative review
The broadest type of research review methods which allows for the simultaneous inclusion of experimental and non-experimental research to more fully understand a phenomenon of concern.
limits
Sets of parameters, often predesignated by the search interface, used to filter or restrict the retrieval to a specific subset, e.g., year or publication type, of the entire database. See FILTERS and HEDGES.
literature review
See NARRATIVE/LITERATURE REVIEW.
literature search
Examination or searching (by hand or online) of bibliographic databases. Often used interchangeably with the phrases "database search" or "online search." A literature search also refers the search results or list of references produced by the search process.
mediated searching
Online searching performed by one person, usually an expert searcher, for someone else (the end user).
meta-analysis
A type of review article that synthesizes the research results from a number of relevant articles by use of specific statistical methods. Meta-analysis is also the process of synthesizing this research.
narrative/literature review
Encompasses reviews of published materials that provide an examination of recent or current literature on a broad and/or wide range of subjects.
natural language
Author's or searcher's words, not necessarily thesaurus or vocabulary terms. The words that the researcher might use in conversation or writing. See KEYWORD.
observational research
Can be used to describe many study designs that are not randomized trials and may or may not have a comparison or control group (i.e., cohort studies or case-control studies that have a goal of establishing causation, studies of prognosis, studies of diagnostics tests and qualitative studies).
PICO
A mnemonic identifying the key elements of a clinical research question in which P stands for patient (or population or problem), I for intervention, C for comparison, and O for outcome.
precision
The proportion of citations in a given search that are relevant to the search question. Precision indicates the specificity of the search.
primary sources
Original studies. See SECONDARY SOURCES and TERTIARY SOURCES.
PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)
An evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. PRISMA primarily focuses on the reporting of reviews evaluating the effects of interventions, but can also be used as a basis for reporting systematic reviews with objectives other than evaluating interventions (e.g. evaluating etiology, prevalence, diagnosis or prognosis).
PROSPERO
An international prospective register of systematic reviews. Key details from new Cochrane protocols are automatically uploaded into PROSPERO. It is produced by the Centre of Reviews and Dissemination, University of York, United Kingdom.
protocol
Written by the SR Team, the SR protocol serves as a roadmap. It includes the research question, context and rationale for the review, study design, search strategy, inclusion/exclusion criteria, procedures for study collection, data collection and extraction, data synthesis, reporting, and other components of the research plan.
proximity operators
Words, phrases, or symbols used to indicate how closely two or more search terms are physically placed in a database record.
rapid review
A type of knowledge synthesis in which components of the systematic review process are simplified or omitted to produce information in a short period time. Review team will determine scope and methods based on time available. Used on emerging issues needing timely answers.
risk of bias
The extent to which flaws in the design and execution of a collection of studies could bias the estimate of effect for each outcome under study.
qualitative question
Seek to discover, describe and understand rather than test or evaluate.
quantitative question
Seek to discover cause and effect relationships by comparing two or more individuals or groups based on different outcomes related to exposures or interventions.
qualitative research
Looks at particular issues in a broad, open-ended way to generate (or modify) hypotheses and prioritize areas to investigate.
quantitative research
Begins with an idea/hypothesis which through measurement generates data and allows a conclusion to be drawn.
recall
The proportion of relevant citations in a given search relative to the total number of relevant citations. Recall indicates the sensitivity of the search.
scientific literature
Refers to theoretical and research publications in scientific journals, reference books, textbooks, government reports, policy statements, and other materials about the theory, practice, and results of scientific inquiry.
scoping review
Provides a preliminary assessment of the potential size and scope of available research literature. It can identify either specific or general opportunities for further research.
search results
The information or list of citations retrieved from a database search. Expert searchers often create additional materials such as cover letters to accompany search results.
search steps
The individual search statements that make up the search strategy. Also called search sets.
search strategy
The overall plan or approach to a database search consisting of one or more steps used to retrieve desired results.
secondary sources
Summarize and draw conclusions from primary studies and include reviews, systematic reviews, meta-analyses, guidelines. See PRIMARY SOURCES and TERTIARY SOURCES.
sensitivity
See RECALL.
specificity
See PRECISION.
study quality
For an individual study, study quality refers to all aspects of a study's design and execution and the extent to which bias is avoided or minimized. A related concept is internal validity, that is, the degree to which the results of a study are likely to be true and free of bias.
subject headings
A list of designated words or phrases used to describe the subject content of items in a database. Subject headings (or indexing terms) can be assigned by indexers or artificial intelligence. See CONTROLLED VOCABULARY and THESAURUS.
subject specialist
In the context of responsible literature searching, the subject specialist is the faculty, researcher or clinician.
systematic review
Seeks to systematically search for, appraise and synthesize research evidence on a specific question, often adhering to guidelines on the conduct of a review.
tertiary sources
Provide distillations, over and information consolidation from primary and secondary information sources and include textbooks, information databases (UpToDate) and official publications.
thesaurus
An alphabetical listing of subject headings that comprise the controlled vocabulary for a particular database. See CONTROLLED VOCABULARY and SUBJECT HEADINGS.
umbrella review
A review of reviews that compiles evidence from existing reviews into one accessible and usable document. It may be conducted when there are competing interventions.