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Glossary of terms

Double-blind study A study in which neither the subject (patient) nor the observer (investigator/
clinician) is aware of which treatment or intervention the subject is receiving.
The purpose of blinding is to protect against bias.
Dysentery An infection of the intestinal tract that causes diarrhoea with blood and mucus.
Dysuria Pain on passing urine.
Economic evaluation A comparison of alternative courses of action in terms of both their costs and
consequences. In health economic evaluations, the consequences should
include health outcomes.
Effectiveness See clinical effectiveness.
Efficacy The extent to which a specific treatment or intervention has a beneficial effect on
the course or outcome of disease compared with no treatment or other routine
care under controlled clinical conditions, for example in a laboratory.
Elective Clinical procedures that are regarded as advantageous to the patient but not
urgent.
Endemic Diseases that are present in or peculiar to particular localities or populations.
Enteric infection Infection of the intestine.
Epidemiology The study of diseases within a population, covering the causes and means of
prevention.
Erythrocyte sedimentation A measure of the settling of red blood cells in a tube of blood during 1 hour. The rate
rate (ESR) is an indication of inflammation and increases in many diseases.
Evidence-based clinical Evidence-based clinical practice involves making decisions about the care of
practice individual patients based on the best research evidence available rather than
basing decisions on personal opinions or common practice (which may not
always be evidence based). Evidence-based clinical practice therefore involves
integrating individual clinical expertise and patient preferences with the best
available evidence from research.
Evidence level A code (e.g. 1++, 1+) linked to an individual study, indicating where it fits into
the hierarchy of evidence and how well it has adhered to recognised research
principles. Also called level of evidence.
Evidence table A table summarising the results of a collection of studies which, taken together,
represent the evidence supporting a particular recommendation or series of
recommendations in a guideline.
Exclusion criteria See selection criteria.
Experimental study A research study designed to test whether a treatment or intervention has an
effect on the course or outcome of a condition or disease, where the conditions
of testing are to some extent under the control of the investigator. Also known
as an intervention study. Controlled clinical trials and randomised controlled
trials are examples of experimental studies.
Experimental treatment A treatment or intervention (e.g. a new drug) being studied to see whether it has
an effect on the course or outcome of a condition or disease.
External validity The degree to which the results of a study hold true in non-study situations, for
example in routine clinical practice. May also be referred to as the generalisability
or applicability of study results to non-study patients or populations.
Focused question A study question that clearly identifies all aspects of the topic that are to be
considered while seeking an answer. Questions are normally expected to
identify the patients or population involved, the treatment or intervention to be
investigated, what outcomes are to be considered, and any comparisons that are
to be made. For example, do insulin pumps (intervention) improve blood sugar
control (outcome) in adolescents with type 1 diabetes (population) compared
with multiple insulin injections (comparison)? See also clinical question.
Forest plot A graphical display of results from individual studies included in a meta-analysis
together with the pooled meta-analysis result. This allows visual comparison of
results from individual studies and examination of the degree of heterogeneity
between studies.

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