Item discrimination refers to the ability of an item to differentiate among students on the basis of how well they know the material being tested. Various hand calculation procedures have traditionally been used to compare item responses to total test scores using high and low scoring groups of students. Computerized analyses provide more accurate assessment of the discrimination power of items because they take into account responses of all students rather than just high and low scoring groups. For items with one correct alternative worth a single point, the item difficulty is simply the percentage of students who answer an item correctly. The item difficulty index ranges from 0 to 100; the higher the value, the easier the question. When an alternative is worth other than a single point, or when there is more than one correct alternative per question, the item difficulty is the average score on that item divided by the highest number of points for any one alternative.
Multiple choice (MC),[1] objective response or MCQ (for multiple choice question) is a form of an objective assessment in which respondents are asked to select only correct answers from the choices offered as a list. The multiple choice format is most frequently used in educational testing, in market research, and in elections, when a person chooses between multiple candidates, parties, or policies. Reliability coefficients theoretically range in value from zero (no reliability) to 1.00 (perfect reliability). In practice, their approximate range is from .50 to .90 for about 95% of the classroom tests scored by ScorePak®. High reliability means that the questions of a test tended to “pull together.” Students who answered a given question correctly were more likely to answer other questions correctly.
Test Items
If it were possible to administer an infinite number of parallel tests, a student’s score would be expected to change from one administration to the next due to a number of factors. For each student, the scores would form a “normal” (bell-shaped) distribution. The mean of the distribution is assumed to be the student’s “true score,” and reflects what he or she “really” knows about the subject. The standard deviation of the distribution is called the standard error of measurement and reflects the amount of change in the student’s score which could be expected from one test administration to another. The measure of reliability used by ScorePak® is Cronbach’s Alpha. This is the general form of the more commonly reported KR-20 and can be applied to tests composed of items with different numbers of points given for different response alternatives.
This is deeply analyzing a single question on English vocabulary, to see if the student knows the word alleviate. About 70% of the students answered correctly, with a very strong point-biserial. The distractor P values were all in the minority and the distractor point-biserials were negative, which adds evidence to the validity. The graph shows that the line for the correct answer is going up while the others are going down, which is good. If you are familiar with item response theory, you’ll notice how the blue line is similar to an item response function. Psychometricians are essential for this step, as the statistical analyses can be quite complex.
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Universities typically do not give much thought to psychometrics even though a significant amount of testing occurs in higher education, especially with the move to online learning and MOOCs. In item banking, problems of item calibration and person scoring are always subject to large numbers of missing data, due to the fact that no person responds to all items in the pool. If new items are calibrated, a few existing items from the pool are added to the tests and their known item parameter values are used to link the new items to the scale already established for the pool. Likewise, if a person is tested, any set of items from the pool can be used as a test. When estimating the person’s score, the estimation equation has known values for the item parameters and automatically accounts for the properties of the items. Consequently, in more statistical terms, differences in item selection do not create any (asymptotic) bias in the ability estimates.
- If the test is in credentialing or pre-employment, psychometricians typically run a job analysis study to form a quantitative, scientific basis for the test blueprints.
- Hambleton and Jones (1994) already warned about the consequences.
- In item banking, items are written, pretested, and calibrated on a continuous basis.
- Test item writers are instructed to make their distractors plausible yet clearly incorrect.
- The multiple choice format is most frequently used in educational testing, in market research, and in elections, when a person chooses between multiple candidates, parties, or policies.
The items should be so worded that all pupils understand the task. List how many tasks need to be accomplished in order to fully respond to the essay prompt below, or another one your instructor will provide for you. Fill in the ____________ questions are featured frequently on exams. Test scores are often used to classify candidates into groups, such as pass/fail (Certification/Licensure), hire/non-hire (Pre-Employment), and below-basic/basic/proficient/advanced (Education). Psychometricians lead studies to determine the cutscores, using methodologies such as Angoff, Beuk, Contrasting-Groups, and Borderline. Where x¯i and x¯ij denotes the sample means and cross products, respectively.
Multiple Choice Test Items
The information gleaned from assessments is critical for teaching and learning; moreover, it is an inflection point through which students can learn, assignments can be bolstered, and curriculum improved. The most serious disadvantage is the limited types of knowledge that can be assessed by multiple choice tests. Multiple choice tests are best adapted for testing well-defined or lower-order skills. This is especially true in the United States and India, where multiple choice tests are the preferred form of high-stakes testing and the sample size of test-takers is large respectively. Usually, a correct answer earns a set number of points toward the total mark, and an incorrect answer earns nothing.
Comparatively, many test items can be presented to students. An essay test may be objective-centered or objective-based, though it may be difficult to score it objectively. An objective type test, on the other hand, can always be scored objectively, though it what is test item may not be objective-centered if it is not planned with reference to the objectives of instruction. The items of a multiple choice test are often colloquially referred to as “questions,” but this is a misnomer because many items are not phrased as questions.
This article emphasizes a systematic process used to develop tests in order to maximize validity evidence for scores resulting from those tests. In item banking, items are written, pretested, and calibrated on a continuous basis. Items that pass the quality criteria are added to a pool of items from which new tests are assembled when needed. Item analysis entails noting the pattern of student errors to various questions in all the ways stated above.
Plausible alternatives serve as functional distractors, which are those chosen by students that have not achieved the objective but ignored by students that have achieved the objective. There is little difference in difficulty, discrimination, and test score reliability among items containing two, three, and four distractors. The profession does not change quickly because things like anatomy never change and medical procedures rarely change (e.g., how to measure blood pressure). So, every 5 years it does a job analysis of its certificants to see what they are doing and what is important. Items are re-mapped if needed, but most likely do not need it because there are probably only minor changes to the blueprints.
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