A test that fosters inference about one kid of behavior or performance through measurement of another related kind of performance. Testing two or more points together, usually implying the testing of a number of such points at once. An example would be a dictation, which could be used to measure listening comprehension, spelling, or general language proficiency. For example, if the upper third of the students get the item correct and the lower two thirds generally get it wrong, the item is a good discriminator between these two groups. In even-numbered distributions with no central score, the median is either the midpoint between the two centerbounding scores or a weighted point between them.
Some distributions are irregular, having more than one mode.
It usually implies standardization through prior administration to a large sample of examinees. This is unlike a subjective test that depends on impression and opinion at the time of scoring. It is also expressible as 100 times the obtained score divided by the total score possible. On an item-based test the raw score is usually equal to the sum of the correct items. It is usually an estimate on a scale of zero to one of the likelihood that the test would rank test takers in the same order from one administration to another proximate one.