Longman Dictionary of

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discrete adj discreteness n
(of a linguistic unit) having clearly defined boundaries.
In PHONOLOGY, the distinctive sound units of a language (the PHONEMES)
are considered to be discrete units. For example, the English word pin
would consist of three such units: /p/, /∂/, and /n/.
discrete-point test n
a language test that measures knowledge of individual language items,
such as a grammar test with different sections on tenses, adverbs, and
prepositions. Discrete-point tests are based on the theory that language
consists of different parts (e.g. grammar, pronunciation, and
vocabulary) and different skills (e.g. listening, speaking, reading, and
writing) and these are made up of elements that can be tested separately.
Tests consisting of MULTIPLE-CHOICE ITEMs are usually discretepoint
tests. Discrete-point tests can be contrasted with INTEGRATIVE
TESTs.
discriminant validity n
also divergent validity
(in testing) a type of CONSTRUCT VALIDITY that is based on the extent to
which two or more tests that are claimed to measure different underlying
CONSTRUCTs are in fact doing so. For example, to establish discriminant
validity of two tests that are claimed to measure the different constructs
(e.g. L2 listening and L2 vocabulary), both tests are administered to the
same group of test takers using the same method (e.g. MULTIPLE-CHOICE
ITEMs for both tests) and the test scores are correlated. If a weak or no
correlation is obtained, this is an indication that they are indeed measuring
different constructs.
see CONSTRUCT VALIDITY, CONVERGENT VALIDITY, MULTI-TRAIT MULTI-
METHOD METHOD
discrimination 1 n
see STIMULUS-RESPONSE THEORY
discrimination
discrimination 2
also discrimination power
(in testing) the degree to which a test or an item in a test distinguishes
among stronger and weaker test takers. For example, if test takers are
known to have different degrees of ability but all score around 85% on a
test, the test fails to discriminate. A measure of the discrimination of a test
is known as a discrimination index.
see also ITEM DISCRIMINATION
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