A5V4d

Abbreviations and glossary
Standard deviation A measure of the spread, scatter or variability of a set of measurements.
Usually used with the mean (average) to describe numerical data.
Statistical power The ability of a study to demonstrate an association or causal relationship
between two variables, given that an association exists. For example, 80%
power in a clinical trial means that the study has a 80% chance of ending up
with a P value of less than 5% in a statistical test (i.e. a statistically significant
treatment effect) if there really was an important difference (e.g. 10% versus
5% mortality) between treatments. If the statistical power of a study is low, the
study results will be questionable (the study might have been too small to
detect any differences). By convention, 80% is an acceptable level of power.
Structured interview A research technique where the interviewer controls the interview by adhering
strictly to a questionnaire or interview schedule with pre-set questions.
Study checklist A list of questions addressing the key aspects of the research methodology that
must be in place if a study is to be accepted as valid. A different checklist is
required for each study type. These checklists are used to ensure a degree of
consistency in the way that studies are evaluated.
Study population People who have been identified as the subjects of a study.
Study quality See methodological quality.
Study type The kind of design used for a study. Randomised controlled trials, case–control
studies and cohort studies are all examples of study types.
Subject A person who takes part in an experiment or research study.
Survey A study in which information is systematically collected from people (usually
from a sample within a defined population).
Symptom A patient’s report of an abnormal feeling or sensation that provides the clinician
with a subjective indication of a particular diagnosis or disorder (cf. sign).
Systematic Methodical, according to plan; not random.
Systematic error Refers to the various errors or biases inherent in a study. See also bias.
Systematic review A review in which evidence from scientific studies has been identified,
appraised and synthesised in a methodical way according to predetermined
criteria. May or may not include a meta-analysis.
Systemic Involving the whole body.
Tachypnoea Abnormally rapid respiratory rate.
Target population The people to whom guideline recommendations are intended to apply.
Recommendations may be less valid if applied to a population with different
characteristics from the participants in the research study, for example in terms
of age, disease state or social background.
Tepid sponging A traditional treatment for fever in which the patient is undressed and sponged
with lukewarm water that is then allowed to evaporate.
Tertiary centre A major medical centre providing complex treatments that receives referrals
from both primary and secondary care. Sometimes called a tertiary referral
centre. See also primary care and secondary care.
Triangulation Use of three or more different research methods in combination; principally
used as a check of validity. The more the different methods produce similar
results, the more valid the findings.
Triple-blind study A study in which the statistical analysis is carried out without knowing which
treatment patients received, in addition to the patients and
investigators/clinicians being unaware which treatment patients were getting.
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