External validity Health Dictionary

The extent to which a measurement, test or study measures what it purports to measure. There are various types of validity: construct validity: The degree to which an instrument measures the characteristic being investigated; the extent to which the conceptual definition matches the operational definition. content validity: Verification that the method of measurement actually measures what it is expected to measure, covering all areas under investigation reasonably and thoroughly. criterion validity: Verification that the instrument correlates with external criteria of the phenomenon under study, either concurrently or predictively. external validity: The extent to which study results can be generalized beyond the sample used in the study. face validity: A type of content validity, determining the suitability of a given instrument as a source of data on the subject under investigation, using commonsense criteria. internal validity: the extent to which the effects detected in a study are truly caused by the treatment or exposure in the study sample, rather than being due to other biasing effects of extraneous variables.... validity

See “validity”.... construct validity

See “validity”.... content validity

See “validity”.... criterion validity

Compression of the outside of the sternum and ribs, effectively emptying and filling the heart to push blood through arteries to supply oxygen to the body - particularly to the brain.... external cardiac compression

See “validity”.... face validity

See “validity”.... internal validity

(AED) a type of external *defibrillator that can analyse the heart rhythm it detects and advise via voice prompts on therapy to be given according to the latest guidelines. In cases of ventricular fibrillation, some defibrillators will make decisions on delivering electric shocks and do so after issuing appropriate warnings to the attending health-care professionals.... automated external defibrillator

(EECP) an experimental treatment for patients with intractable angina. Specially designed inflatable trousers are inflated rhythmically in time with ventricular *diastole. Theoretically this imparts additional energy to the circulating blood volume when the heart is relaxed, and this may improve blood flow down severely narrowed coronary arteries. It is also claimed to have beneficial effects on blood flow to other organs. Despite promising clinical trials, this technique has not been widely adopted.... enhanced external counterpulsation

see teletherapy.... external beam radiotherapy

an apparatus consisting of a rigid frame that connects pins passed through the skin into the bone above and below a fracture. This immobilizes the fracture, and is used particularly to treat some compound fractures. An external fixator is also used for *limb lengthening.... external fixator