TESTING:

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n educational assessment, testing is a cognitive investigative string in an educational system that may involve several tests as a means of assessing a learner given several subject matter areas.

A Test: Just as a meter rule is a physical measurement instrument, a test is a psychological or educational measurement instrument. A meter rule is a systematic arrangement of calibrated marks on a piece of wood or metal each mark representing a given amount of length or height which must be matched by what is being measured before it could be said to be of that length or height. Similarly, a test is a collection of devotedly developed and calibrated items arranged systematically to provide a means of quantifying the amount of what is being measured that a person, body or event possesses. Hence a test provides a calibrated line along which the amount of trait or ability under measurement possessed by an individual can be located.      

Test item: In educational measurement, a test is like a meter rule and an item determines one calibrated mark on the rule.  In cognitive testing, an item is a calibrated cognitive task, statement or problem which when presented to the learner elicits from him/her the amount of behaviour under measurement called for in the course objective such that the learner’s reaction to it reflects how much of the desired behaviour or knowledge he/she possesses or has acquired.  During testing, a testee comes to the testing scene equipped with his/her level of ability or knowledge demanded by the test. An item is designed to pose a cognitive challenge to, or cognitive demand on the level of ability under measurement possessed by an individual and hence to elicit or provoke such ability into action. The ability is latent and not seen nor can it be perceived hence to measure it, it has to be provoked into action by posing a task or problem that calls on it for solution. Such task or problem is called an item. Therefore an item serves as a stimulus to the latent ability or knowledge possessed by the individual or acquired during a course. To be a good item, it must be constructed to illicit the desired ability only and in such a way that only those who possess the desired ability to a level that matches the cognitive resistance of an item can react correctly to it. An item’s cognitive resistance or demand is the ability just necessary to overcome the item. Each item has a specific amount of cognitive demand which determines its place on the measurement line for the desired ability or trait.