Item Discrimination
Discuss what is meant by item discrimination. How can it be assessed? What are the consequences for item selection when the criteria are total test scores as opposed to external scores?

Item discrimination alludes to the capacity of an item to distinguish among students on an intellectual foundation of how well they are accustomed to the substance being tested (Anastasi, & Urbina, 1997). Previously, calculations were manually employed to compare item responses to total test scores using high and low scoring groups of students. Computer computation yields more robust assessment of the discrimination power of items because they take into consideration all students responses rather than just high and low scoring groups. Similarly, it is relevant for buildup instructors' skills in test development, and distinguishing explicit regions of course content, which need exceptional explicitness. Item discrimination shows the degree to which favorable outcome on a material is identical to success on the entire test since all materials in a test are meant to stand shoulder to shoulder to produce an overall test score. Any material lacking positive qualities or zero discrimination weakens the test. Positive item discrimination is usually prolific, unless it is so high that the material simply duplicates the information produced by other materials on the test (Lord, 1952).
Item discrimination indicators must at all times be explained in the surrounding text of the type of test being examined methodically in order to be valid. To achieve this, the articles to be examined must be valid criteria of instructional intentions. The items must be diagnostic that is, knowledge of which inaccurate choices students elect must be a clue to the nature of the disagreement, and so prescriptive of relevant remediation. Items with low discrimination indices are often