ITEM - In Linden, K.W. (1985) Designing tools for assessing...

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In Linden, K.W. (1985) Designing tools for assessing classroom achievement: A handbook of materials and exercises for Educational 524 . ITEM ANALYSIS AND EVALUATION PROCEDURES I. Evaluation of the effectiveness of the items in a test requires answers to the following questions dealing with distribution of responses , discriminating power of the item , and difficulty value of the item : Distribution of Responses: Did the distractors (incorrect response choices) prove to be attractive to students who did not know the correct answer? Did the distractors or the stem contain ambiguities? Discriminating Power of the Item (D): Did the item discriminate between “good” and “poor” students? That is, did more of the students obtaining high scores on the test as a whole get the item right than did students who made low scores on the test as a whole? Difficulty Value of the Item (P): Was the item high, low or medium in difficulty? What was the tendency of the test as a whole with respect to the difficulty of the items? In the following sections, each of the above questions is discussed specifically, and a method is recommended for determining the answer to each question. Certain of these questions are evaluated by means of a study of the pattern of responses; others are described mathematically by numerical indices. The methods of item analysis described are applicable to groups as small as 30 cases. However, with small groups, the discrimination index and the difficulty value will tend to fluctuate more from one use go another than they will with large groups (approximately 100 cases or more). In order to obtain reasonably stable estimates of discriminating power and difficulty value from one administration , it is suggested that at least 100 students take the test. If this is not possible, item data can be cumulated from several groups taking the same test. II. Distribution of Responses A. Directions for obtaining the distribution of responses: 1. Place the test papers in order of score from the highest to the lowest. 2. Select the 27% of the papers having the highest scores and the 27% of the papers having the lowest scores.
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3. For each item in turn, tabulate the number of students in the top 27% (designated the High group, H) and the number of students in the bottom 27% (designated the Low group, L) choosing each possible response to the item. B. The tabulation of the following four-choice objective item might look like this: Item 38: The height of the tide is dependent, in part, upon the position of the moon in relation to the (A) planets (b) earth (c) plane of the ecliptic (d) sun Item No. Responses Group Omit A B* C D NR 38 H 17 15 3 5 L 3 11 3 12 0 1 Thus, for item number 38, 17 students in the high group chose distracter A; 15 chose the
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ITEM - In Linden, K.W. (1985) Designing tools for assessing...

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