GLOSSARY
OF TERMS
     
     
C
Case
series
An
uncontrolled observational study involving an intervention and
outcome for more than one person
Case
study
(synonyms: anecdote, case history, single case report)
An uncontrolled observational study involving an intervention
and outcome for a single person.
Case-control
study
(synonyms: case referent study, retrospective
study)
A study that starts with identification of people with the
disease or outcome of interest (cases) and a suitable
control group without the disease or outcome. The relationship
of an attribute (intervention, exposure or risk
factor)
to the outcome of interest is examined by comparing the frequency
or level of the attribute in the cases and controls. For example,
to determine whether thalidomide caused birth defects
a group of children with birth defects (cases) could be compared
to a group of children without birth defects (controls).
The groups would then be compared with respect to the
proportion exposed to thalidomide through their mothers taking
the tablets. Case-control studies are sometimes described
as being retrospective
studies
as they are always performed looking back in time.
CD-ROM
(Compact Disc - Read Only Memory)
A computer storage medium. A CD-ROM can contain a database
of information (e.g. MEDLINE,
or the Cochrane
Controlled Trials Register)
that may be searched either on a personal computer or a computer
linked to a network.
CDSR
See
Cochrane
Database of Systematic Reviews.
CI
See
Confidence
interval
CINAHL
(Cumulative Index of Nursing and Allied Health Literature)
An electronic database covering the major journals in nursing
and allied health. Years of coverage: 1983 - present.
CL
See
Cochrane
Library
Clinical
trial (synonyms:
therapeutic trial, intervention study)
A trial that tests out a drug or other intervention to assess
its effectiveness and safety. This general term encompasses
randomized-controlled
trials
and controlled
clinical trials.
Cochrane Collaboration
An
international organization that aims to help people make well
informed decisions about health by preparing, maintaining and
ensuring the accessibility of systematic reviews of the
benefits and risks of healthcare interventions.
More information on the Cochrane Collaboration is available
from the Cochrane
Library
Cochrane Controlled Trials Register
(CCTR)
A database of references to controlled trials in health
care. Cochrane groups and other organizations have been invited
to contribute their specialized registers, and these registers,
together with references to clinical trials identified on MEDLINE,
form the CENTRAL register of studies. Records from CENTRAL,
following quality control to try to ensure that only reports
of definite randomized controlled trials or controlled clinical
trials are included, make up The Cochrane Controlled Trials
Register (CCTR).
Cochrane Database of Systematic Reviews
(CDSR)
The major product of the Cochrane Collaboration. It brings
together all the currently available Cochrane Reviews
and is updated quarterly. It also contains information about
the Collaboration. See Cochrane
Library.
Cochrane
Library (CL)
A collection of databases, published on disk and CD-ROM
and updated quarterly, containing the Cochrane
Database of Systematic Reviews,
the Cochrane
Controlled Trials Register,
the Database
of Abstracts of Reviews of Effectiveness,
the Cochrane Review Methodology Database, and information about
the Cochrane Collaboration.
Cohort
study
(synonyms: follow-up, incidence, longitudinal, prospective
study)
An observational study in which a defined group of people
(the cohort) is followed over time and outcomes are compared
in subsets of the cohort who were exposed or not exposed,
or exposed at different levels, to an intervention or other
factor of interest. Cohorts can be assembled in the present
and followed into the future (a "concurrent cohort study"),
or identified from past records and followed forward from that
time up to the present (a "historical cohort study").
Because random allocation is not used, matching or statistical
adjustment must be used to ensure that the comparison groups
are as similar as possible.
Cointervention
In
a randomized
controlled trial,
the application of additional diagnostic or therapeutic
procedures to members of either or both the experimental and
the control groups.
Concealment
of allocation
The
process used to prevent foreknowledge of group assignment in
a randomized-controlled
trial,
which should be seen as distinct from blinding. The allocation
process should be impervious to any influence by the individual
making the allocation by having the randomization process administered
by someone who is not responsible for recruiting participants;
for example, a hospital pharmacy, or a central office. Using
methods of assignment such as date of birth and case record
numbers (see quasi-random
allocation)
are open to manipulation. Adequate methods of allocation
concealment include: centralized randomization schemes; randomization
schemes controlled by a pharmacy; numbered or coded containers
in which capsules from identical-looking, numbered bottles are
administered sequentially; on-site computer systems, where allocations
are in a locked unreadable file; and sequentially numbered opaque,
sealed envelopes.
Conference
abstracts
Short
summaries of presentations at conferences. May be published
as proceedings.
Confidence
interval
(CI)
The range within which the "true" values (e.g.
size of effect of an intervention) is expected to lie
with a given degree of certainty (e.g. 95% or 99%). Note: Confidence
intervals represent the probability of random
errors,
but not systematic errors (bias).
Confounding
A
situation in which a measure of the effect of an intervention
or exposure is distorted because of the association of
exposure with other factor(s) that influence the outcome under
study.
Consumer
(healthcare
consumer)
Someone, who uses, is affected by, or who is entitled or
compelled to use a health related service.
Consumer
advocate or representative
Consumer
who is actively involved with other consumers and able to represent
the perspectives and concerns of that broader group of people.
A consumer advocate, or representative, should be linked with
other consumers, accountable to them, and should not have a
conflict of interest in that role.
Contamination
In
clinical trials, the inadvertent application of the intervention
being evaluated to people in the control group or inadvertent
failure to apply the intervention to people assigned to the
intervention group.
Control
- In
clinical trials comparing two or more interventions, a control
is a person in the comparison group that receives a placebo,
no intervention, usual care or another form of care.
- In
case-control
studies
a control is a person in the comparison group without
the disease or outcome of interest.
- In
statistics control means to adjust for or take into account
extraneous influences or observations.
- Control
can also mean programs aimed at reducing or eliminating the
disease when applied to communicable (infectious) diseases.
Controlled clinical trial
(CCT)
Refers to a study that compares one or more intervention
groups to one or more comparison (control)
groups. Whilst not all controlled studies are randomized,
all randomized trials are controlled
Cost-benefit
analysis
An
economic analysis that converts effects into the same monetary
terms as the costs and compares them.
Cost-effectiveness analysis
An
economic analysis that converts effects into health terms and
describes the costs for some additional health gain (e.g.
cost per additional stroke prevented).
Cost-utility
analysis
An
economic analysis that converts effects into personal preferences
(or utilities) and describes how much it costs for some additional
quality gain (e.g. cost per additional quality-adjusted life-year).
Critical
appraisal
The
process of assessing and interpreting evidence by systematically
considering its validity, results and relevance.
Cross-sectional
study
(synonym: prevalence study)
A study that examines the relationship between diseases
(or other health related characteristics) and other variables
of interest as they exist in a defined population at one particular
time. The temporal sequence of cause and effect cannot necessarily
be determined in a cross-sectional study.
Cross-over
trial
A
type of clinical trial comparing two or more interventions in
which the participants, upon completion of the course
of one treatment are switched to another. For example, for a
comparison of treatments A and B, half the participants are
randomly allocated to receive them in the order A, B and half
to receive them in the order B, A. A problem with this
design is that the effects of the first treatment may carry
over into the period when the second is given.
Current
Contents
Electronic
database that provides access to the tables of contents and
bibliographic data from current issues of the world's leading
scholarly research journals in the sciences, social sciences,
arts and humanities. Over 6,600 journals covered.
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