Item Analysis
Psychometrics I (PSY - 401)
Item Analysis and types of item analysis
Item Analysis allows us to observe the characteristics of a particular question (item) and can be used to ensure that questions are of an appropriate standard and select items for test inclusion. Introduction Item Analysis describes the statistical analyses which allow measurement of the effectiveness of individual test items. An understanding of the factors which govern effectiveness (and a means of measuring them) can enable us to create more effective test questions and also regulate and standardize existing tests. The term item analysis refers to a group of statistics that can be calculated for individual test items. There are a variety of item statistics that can be computed and a variety of calculation techniques. The Three most commonly used statistics are item difficulty, item discrimination and distractor power. Although these statistics are usually discussed in regard to multiple-choice ability tests, two of them, item difficulty and item discrimination, can be adapted to the analysis of short-answer and essay questions and are also used on personality, interest, and altitude tests.
Purpose of Item Analysis
Evaluates the quality of each item Rationale: the quality of items determines the quality of test (i.e., reliability & validity) May suggest ways of improving the measurement of a test Can help with understanding why certain tests predict some criteria but not others
When analyzing the test items, we have several questions about the performance of each item. Some of these questions include: Are the items congruent with the test objectives? Are the items valid? Do they measure what they 're supposed to measure? Are the items reliable? Do they measure consistently? How long does it take an examinee to complete each item? What items are most difficult to answer correctly? What items are easy? Raumish Masud Khan Assistant Professor Department of Applied Psychology Kinnaird
Item Analysis and types of item analysis
Item Analysis allows us to observe the characteristics of a particular question (item) and can be used to ensure that questions are of an appropriate standard and select items for test inclusion. Introduction Item Analysis describes the statistical analyses which allow measurement of the effectiveness of individual test items. An understanding of the factors which govern effectiveness (and a means of measuring them) can enable us to create more effective test questions and also regulate and standardize existing tests. The term item analysis refers to a group of statistics that can be calculated for individual test items. There are a variety of item statistics that can be computed and a variety of calculation techniques. The Three most commonly used statistics are item difficulty, item discrimination and distractor power. Although these statistics are usually discussed in regard to multiple-choice ability tests, two of them, item difficulty and item discrimination, can be adapted to the analysis of short-answer and essay questions and are also used on personality, interest, and altitude tests.
Purpose of Item Analysis
Evaluates the quality of each item Rationale: the quality of items determines the quality of test (i.e., reliability & validity) May suggest ways of improving the measurement of a test Can help with understanding why certain tests predict some criteria but not others
When analyzing the test items, we have several questions about the performance of each item. Some of these questions include: Are the items congruent with the test objectives? Are the items valid? Do they measure what they 're supposed to measure? Are the items reliable? Do they measure consistently? How long does it take an examinee to complete each item? What items are most difficult to answer correctly? What items are easy? Raumish Masud Khan Assistant Professor Department of Applied Psychology Kinnaird
References: http://caacentre.lboro.ac.uk/resources/bluepapers/index.shtml http://www.specialconnections.ku.edu/?q=assessment/quality_test_construction/tea cher_tools/item_analysis Raumish Masud Khan Assistant Professor Department of Applied Psychology Kinnaird College For Women Lahore