A systematic review and economic model of the effectiveness and ...

Glossary
Adverse effect An abnormal or harmful
effect caused by and attributable to exposure to
a chemical (e.g. a drug), which is indicated by
some result such as death, a physical symptom
or visible illness. An effect may be classed as
adverse if it causes functional or anatomical
damage, causes irreversible change in the
homeostasis of the organism or increases the
susceptibility of the organism to other chemical
or biological stress.
Attention deficit hyperactivity disorder A
mental disorder characterised by a persistent
pattern of inattention and/or
hyperactivity–impulsivity that is more
frequently displayed and more severe than is
typically observed in individuals at a
comparable level of development.
Bias Deviation of results or inferences
from the truth, or processes leading to
such deviation. Any trend in the collection,
analysis, interpretation, publication or
review of data that can lead to conclusions
that are systematically different from the
truth.
Blinding (synonym: masking) Keeping
secret group assignment (e.g. to treatment
or control) from the study participants or
investigators. Blinding is used to protect
against the possibility that knowledge of
assignment may affect patient response to
treatment, provider behaviours (performance
bias) or outcome assessment (detection bias).
Blinding is not always practical (e.g. when
comparing surgery with drug treatment).
The importance of blinding depends on
how objective the outcome measure is;
blinding is more important for less objective
outcome measures such as pain or quality
of life.
Health Technology Assessment 2006; Vol. 10: No. 23
Glossary and list of abbreviations
Technical terms and abbreviations are used throughout this report. The meaning is usually clear from
the context, but a glossary is provided for the non-specialist reader. In some cases, usage differs in the
literature, but the term has a constant meaning throughout this review.
© Queen’s Printer and Controller of HMSO 2006. All rights reserved.
Chi-squared (2 ) test Any statistical test
based on comparison of a test statistic with a
chi-squared distribution.
Concealment of allocation The process used
to prevent foreknowledge of group assignment
in a randomised 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 randomisation process
administered by someone who is not
responsible for recruiting participants, for
example, a hospital pharmacy or a central
office. Methods of assignment such as date of
birth and case record numbers (see quasirandom
allocation) are open to manipulation.
Adequate methods of allocation concealment
include: centralised randomisation schemes;
randomisation 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.
Conduct disorder A mental disorder
characterised by a repetitive and persistent
pattern of behaviour in which the basic rights
of others or major age-appropriate societal
norms or rules are violated, manifested by
aggressive, defiant or antisocial behaviours.
Confidence interval A measure of precision
of statistical estimate; quantifies the uncertainty
in measurement. Usually reported as 95% CI,
i.e. the range of values within which one can be
95% sure that the true values for the whole
population lie.
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