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Evidence-Based Toxicology Collaboration

Evidence-based Toxicology Glossary


Advisory group
A group of people including representation of relevant stakeholders, with relevant interests, skills and commitment to support the review team, e.g., in key decisions, interpretation and dissemination

Attrition bias
Bias due to systematic differences between treatment and comparison groups in withdrawals or exclusions from the results of a study.

A systematic error or deviation from the truth in results or inferences. A common classification scheme for biases of individual studies includes selection bias, performance bias, attrition bias, detection bias, while publication bias refers to a set of studies

Cochrane organizes medical research information in a systematic way to facilitate the choices that health professionals, patients, policy makers and others face in health interventions according to the principles of evidence-based medicine

Comprehensive search strategy
The exact terms and their combinations (including Boolean operators) used to search a bibliographic database designed to be sensitive, i.e., not to miss relevant evidence

A situation in which a measure of the effect is distorted because of an association between the intervention (or exposure) with other factor(s) that influence the outcome under investigation

Data extraction
Data extraction is the process of retrieving primarily study characteristics and outcome data, out of included evidence sources for further data processing

Detection bias
Detection bias refers to bias due to systematic differences between groups in how outcomes are determined.

Eligibility criteria
Pre-defined criteria are derived from the review question and used to select eligible studies, i.e., those to be included in the systematic review

Evidence-based medicine (EBM)
Evidence-based medicine is the conscientious explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research

Evidence-based toxicology (EBT)
The discipline of evidence-based toxicology is a process for transparently, consistently, and objectively assessing available scientific evidence to answer questions in toxicology

Evidence-based Toxicology Collaboration (EBTC)
Evidence-based Toxicology Collaboration is a collaboration of science regulatory and industry leaders, united in their vision to improve the public health outcomes and reduce human impact on the environment by bringing evidence-based approaches to safety sciences

Evidence stream
Toxicological evidence can be assigned to evidence streams, i.e., sets of studies representing the same type or level of evidence—e.g., human (observational) studies, animal studies, in vitro or mechanistic studies

External validity
The degree to which the results of a study hold true in other settings (generalisability).

Gray literature
Gray literature is material either unpublished or not controlled by commercial publishers often differing in form, e.g., not a scientific article or report, and the way it is available, i.e., not in journals or databases

Used in a general sense to describe the variation in or diversity of, participants, interventions, and measurement of outcomes across a set of studies, or the variation in internal validity of those studies. Used specifically, as statistical heterogeneity, to describe the degree of variation in the effect estimates from a set of studies. Also, used to indicate the presence of variability among studies beyond the amount expected due solely to the play of chance

Internal validity
The degree to which a result of a study is likely to be free of bias (systematic errors), i.e., has measured what it had intended to measure

The process of synthesizing outcome data from a number of independent studies using statistical methods.

Methodological quality
The extent to which a study is likely to be free of features that reduce trust in the results including internal validity and aspects such as ethical approval, reporting and statistical power

Narrative review
Expert summary of a set of publications from which conclusions are drawn without a detailed and transparent description of what was done to allow reproduction

The components of population/participants, exposure, control/comparison and outcome that the question of a systematic review of an exposure should cover.

Performance bias
Performance bias refers to bias due to systematic differences between groups in the care that is provided or in exposure to factors other than the interventions of interest

The components of population/participants, intervention, control/comparison and outcome that the question of a systematic review of an intervention should cover

The plan or set of steps to be followed in a study. A protocol for a systematic review should describe the rationale for the review the objectives, and the methods that will be used to locate, select, and critically appraise studies, and to collect and analyze data from the included studies

Publication bias
Publication bias is caused when only a subset of all relevant studies is published. The publication of research often depends on the nature and direction of the study results.

Reporting bias
Reporting bias is introduced when only selected outcomes are reported (applying both to systematic reviews and primary studies).

Reporting quality
Reporting quality describes how well and complete a study is reported, ultimately allowing reproduction

Review team
The team that conducts the systematic review with ideally all the various required areas of expertise represented

An approach to searching the literature that can be used to support decisions about whether it is possible or worthwhile proceeding with a systematic review.

Selection bias
Selection bias refers to bias due to systematic differences between baseline characteristics of the groups that are compared.

Sensitivity analysis
An analysis used to test the robustness of findings and determine how sensitive results are to the data that were included and/or the way that analyses were done.

Subgroup analysis
In the context of a meta-analysis subgroup analyses compare the effect sizes of different subgroups of studies/experiments within the included evidence. Subgroup analyses may be conducted as a means of investigating heterogeneous results, or to answer specific questions about particular subgroups (e.g., if the effect depends on sex)

Systematic review
A review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review

Weight-of-evidence is a process of taking into account different types of scientific evidence based on the strength and limitations of individual studies, in assessing the validity of a causal hypothesis, usually referring to both evidence syntheses within the individual evidence streams and to the evidence integration across evidence streams

Source: Hoffmann S, de Vries RBM, Stephens ML, Beck NB, Dirven HAAM, Fowle JR 3rd, Goodman JE, Hartung T, Kimber I, Lalu MM, Thayer K, Whaley P, Wikoff D, Tsaioun K. (2017). A primer on systematic reviews in toxicology.  Archives of Toxicology,  doi: 10.1007/s00204-017-1980-3.

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