a type of validity evidence a posteriori validity evidence “scoring validity” a measure of the stability of test scores a prerequisite for measurement validity
Test-retest reliability Internal consistency Marker reliability Parallel forms reliability Types of scoring validity (methods of estimating reliability)
uusing one test twice for the same test-takers tthe period between the two tests is long enough for test-takers to forget the test but not too long bbetween the two tests, no lesson is given Test-retest reliability
uuse two different but equivalent forms of the test to the same test-takers tthe two tests can be applied in close succession Parallel forms reliability
AA variation of parallel forms reliability; UUsing parallel statistic on one test and dividing the test into two halves for statistics or estimating the correlation of each items in the test with another; FFocuses on the consistency with each other of a test’s internal elements.
EExcel correlation KKuder-Richarson 20 or 21 CCronbach’s alpha
AAdvantages : SSaving time and expenses; HHigher value compared with the test-retest and parallel forms DDisadvantages : LLack of temporal stability of the scores as they result from a single administration of the test; NNot easy to determine the level of difficulty of the items; TThe items in one half may not be equivalent to the items in the other half.
eenvironmental factors; cconstruct, content, theory-based validity; ddefine the level of difficulty/ease of the items ddefine the level of difficulty in reading texts and their questions