Pdf classical test theory ctt vs item response theory irt. Item response theory models student ability using question level performance instead of aggregate test level performance. Classical test theory and item response theory analyses of. Introduction to classical test theory ji zeng and adam wyse. However, few studies have empirically examined the. Basics of classical test theory theory and assumptions types of reliability example classical test theory classical test theory ctt often called the true score model called classic relative to item response theory irt which is a more modern approach ctt describes a set of psychometric procedures used to test items and scales. Applying item response theory modeling in educational research. To provide comparisons and a worked example of item and scalelevel evaluations based on three psychometric methods used in patientreported outcome developmentclassical test theory ctt, item response theory irt, and rasch measurement theory rmtin an analysis of the national eye institute visual functioning questionnaire vfq25. Marlow a, kirsten mccaffery c, gregory zimet d a health behaviour research centre, department of epidemiology and public health, ucl gower street, london wc1e 6bt, uk b healthy communities research centre, faculty of health. Comparison of classical test theory and item response theory and their. Application to truescore prediction from a possibly nonparallel test. As its name indicates, irt primarily focuses on the item level information in contrast to the ctts. Classical test theory is an influential theory of test scores in the social sciences.
Classical test theory and item response theory in automated assembly of parallel test forms the journal of technology, learning, and assessment volume 6, number 8 april 2008 a publication of the technology and assessment study collaborative caroline a. Item response theory irt vs classical test theory ctt. Item reponses theory ctt testoriented indices like reliability are groupspecific scores are testspecific contribution of item measured using other items e. Reliability is seen as a characteristic of the test and of. In psychometrics, item response theory irt also known as latent trait theory, strong true score theory, or modern mental test theory, is a paradigm for the design, analysis, and scoring of tests, questionnaires, and similar instruments measuring abilities, attitudes, or other variables. Comparison of classical test theory and item response. Item response theory, graded response model, psychological assessment, affects background valid and reliable measures are essential to the field of psychology, as well as, to the study of abilities, aptitudes, and attitudes.
Despite its brevity, it has proved its value in classical test theory and item response theory assessments, the three traits have different correlates, and the measures appear to cover the range of subtraits e. The practice of testing has become increasingly common and the reliance on information gained from test scores to make decision has made an indelible mark on our culture. Psychometric theory offers two approaches in analyzing test data. Item response theory is a newer theory with a focus on test items that adds more tools for solving measurement problems in psychology test bias adaptive testing item selection ctt focuses more on the total score of a scale or subscale. On the relationship between classical test theory and item. Classical test theory ctt has served measurement practitioners for several decades as the foundation measurement theory. But such relationships have rarely been empirically investigated, and, as a result, they are largely unknown. An empirical comparison of item response theory and classical. Despite theoretical differences between item response theory irt and classical test theory ctt, there is a lack of empirical knowledge about how, and to what extent, the irt and cttbased item and person statistics behave differently. Trait true score observed score classical test theory. What it is and how you can use the irt procedure to apply it xinming an and yiufai yung, sas institute inc. Item response theory irt model differs in terms of the number of parameters contained in the model. Item response theory painted a more promising picture than classical test theory for the 2 communication items that assessed access to an interpreter when needed. Anothermilestonewaslaidin 1937 with the publication of the kuderrichardson formulas.
Methodological issues regarding power of classical test. This event was followed, shortly thereafter, bytheidea. Two main types of analytical strategies can be found for these data. Demonstrating the difference between classical test theory and item response theory using derived test data. Individual change assessment can be conducted using either the methodologies of classical test theory ctt or item response theory irt. Item response theory irt, also called latent trait theory, is a psychometric theory that was created to better understand how individuals respond to individual items on psychological and educational tests. Summary this chapter presents an overview of classical test theory ctt, strong true. Distinguishing differences compare and contrast topics from the lesson, such as classical test theory and item response theory making connections use understanding to explain the concept of. Test dependent item response theory is essentially a nonlinear common factor model mcdonald, 1999, p. The behavior of the item and person statistics derived from these two measurement frameworks was examined analytically and empirically using a data set obtained from bilog r.
Clinical psychologists are advised to assess clinical and statistical significance when assessing change in individual patients. Validation of a measure of knowledge about human papillomavirus hpv using item response theory and classical test theory jo waller a. The new psychometrics item response theory classical test theory is concerned with the reliability of a test and assumes that the items within the test are sampled at random from a domain of relevant items. Buchanan missouri state university summer 2016 this lecture covers item factor analysis and item response theory from the. Mde scrutinizes items with corrected itemtest correlation less than 0. Higher itemtest correlation is desired, which indicates that high ability examinees tend to get the item correct and low ability examinees tend to get the item incorrect. Sep 09, 2009 this is in sharp contrast to classical test theory, where such an examinee would get a high test score on the easy test and vice versa under item response theory, the examinees ability is fixed and invariant with respect to the items used to measure it. Educational and psychological measurem june 1998 v58 n3 p357. Eric ed466779 classical test theory and item response. Applying item response theory modeling in educational research daitrang le iowa state university follow this and additional works at. Comparison of classical test theory and item response theory and their applications to test development ronald k. The study aimed to examine the construct validity and reliability of the quality of life enjoyment and satisfaction questionnaireshort form qlesqsf according to both classical test and item response theories. Jan 23, 2014 item response theory or irt is a theory in psychometrics that is based on the assumption that individual answers or responses to questions have actual mathematical relationships. Common test theory models include classical test theory ctt and item response theory irt.
Two understandings of one highstakes performance exam. Classical test theory and item response theory comparison of the. Basics of classical test theory california state university. It is sometimes referred to as the strong true score theory or modern mental test theory because irt is a more recent body of theory and. Comparisons between classical test theory and item. Comparing classical test theory and item response theory. The purposes of this instructional module are a to focus attention on the similarities and differences between classical test theory and item response theory and related. T or f item response theory has the advantage over classical test theory in that it provides more detailed information regarding each item on a test. Classical test theory as a firstorder item response theory. Irt, on the other hand, is more theory grounded and models the probabilistic distribution of examinees success at the item level. Educational and psychological measurement, 76, 325338.
The conceptual foundations, assumptions, and extensions of the basic premises of ctt have allowed for the development of some excellent psychometrically sound scales. In this sense, classical test theory ctt has been extensively serving the testing field for about 100 years. Item response theory is a general statistical theory about examinee item and test performance and how performance relates to the abilities that are measured by the items in the test. Educational and psychological measurem june 1998 v58 n3. Classical test theory and item response theory 2016. Item response theory irt, also known as latent trait theory or modern mental test theory. It is sometimes referred to as the strong true score theory or modern mental test theory because irt is a more recent body of theory and makes stronger assumptions as compared to classical test theory. Another branch of psychometric theory is the item response theory irt. Classical test theory and irt are widely used to address measurementrelated issues that arise from commonly used assessments in medical education, including. Pdf test theory, classical test theory researchgate. The study answered the following objectives\nspecifically. Pdf a primer on classical test theory and item response theory for. True t or f cross cultural fairness in testing has always been a critical factor in the development of tests. It is a theory of testing based on the relationship.
The following demonstrates a simulated dataset of 20 students true scores and their raw scores on a 10item test. Classical test theory ctt and item response theory irt classical test theory ctt and item response theory irt are testing item assessment approaches. Article information, pdf download for item response theory and classical test. Pdf a comparative study of classical theory ct and. On the relationship between classical test theory and item response theory. Internal consistency reliability estimates for the scales ranged from 0. It is a theory of testing based on the relationship between individuals performances on a test item and. Classical test theory vs item response theory by chris. Classical test theory ctt and item response theory irt are widely perceived as representing two very different measurement frameworks. Nov 30, 2010 this study compares the psychometric utility of classical test theory ctt and item response theory irt for scale construction with data from higher education student surveys.
Using classical test theory, item response theory, and. Comparisons between classical test theory and item response. From classical test theory to item response theory and back. The measurement models better known and used currently are mentioned, the classical test theory ctt, and item response theory irt, including the rasch model. In psychometrics, item response theory irt also known as latent trait theory, strong true score theory, or modern mental test theory is a paradigm for the design, analysis, and scoring of tests, questionnaires, and similar instruments measuring abilities, attitudes, or other variables. Mar 25, 2010 patientsreported outcomes pro are increasingly used in clinical and epidemiological research. An ncme instructional module on comparison of classical test.
A primer on classical test theory and item response theory. Via a ctt and irt analysis it was found that both assessments are essentially equal in overall difficulty. Item response theory postulates a nonlinear regression of a persons responses to a test item on his or her latent ability a concept that is similar to true score in ctt. The present report demonstrates the difference between classical test theory ctt and item response theory irt approach using an actual test data for chemistry junior high school students. May 31, 2015 classical test theory ctt and item response theory irt classical test theory ctt and item response theory irt are testing item assessment approaches. However, this is only partially reflected in the psychometric practice. Measurement theories are important to practice in educational measurement because they provide a background for addressing measurement problems. Through irt, the abilities or intelligence of people are said to be measurable through various mathematical models and techniques. Classical test theory analyses identified 5 of 10 communication items that did not perform well. Classical test theory assumptions, equations, limitations, and item analyses c lassical test theory ctt has been the foundation for measurement theory for over 80 years. An application of item response theory to psychological test. In psychometrics, the theory has been superseded by the more sophisticated models in item response theory irt and generalizability theory g theory. It is pointed out that popular item response models can be directly obtained from classical test theory based models by accounting for the discrete.
This chapter presents an overview of classical test theory ctt, strong true. Classical test theory vs item response theory by chris allred. You design test items to measure various kinds of abilities such as math ability, traits such as. Public access theses and dissertations from the college of education and human sciences. Item response theory columbia university mailman school. A test theory model is necessary to help us better understand the relationship that exists between the observed or actual score on an examination and the underlying proficiency in the domain, which is generally unobserved.
Item response theory irt is all about your performance on an exam, and how it relates to individual items or questions on a test. Subsequently, the framework of classical theory was elaborated and refined by spearman, george udny yule, truman lee kelley, and others over the quarter century or so following 1904. The history, theoretical frameworks of classical test theory, item response theory irt, and the most common irt models used in modern testing are presented. Classical test theory is based on a set of assumptions regarding the properties of test scores. Hambleton professor of education and psychology at the university of massachusetts, hills south, room 152, amherst, ma 01003.
Overview of classical test theory and item response theory. Abstract item response theory irt is concerned with accurate test scoring and development of test items. However, whether irt or ctt would be the most appropriate method to analyse pro data remains unknown. Classical test theory and item response theory the wiley. Irt is an example of what psychologists call a latent trait. Irt may be regarded as roughly synonymous with latent trait theory. Item response theory provides powerful analytical tools that, even in their most basic applications, can be a valuable. We propose here that item response theory analyses complements the basic ctt techniques presented in janssen and meier 20. Classical test theory ctt and item response theory irt. Approach 2 as an alternative approach for obtaining item response models from appropriate cttbased models or conversely, one can use the following procedure based on an important assumption made when fitting latent variable models to data from discrete observed measures, which is.
Exploratory factor analysis \nvalidity principal component analysis \nreliability confirmatory factor analysis \ nclassical test theory structural equation modeling \ngeneralizability theory measurement invariance \nitem response theory computerized adaptive testing \nmanyfacet rasch model network psychometrics \n\n \nprice. One of the most important problems is dealing with the measurement errors. The psychometric properties of the french version of this instrument were investigated in a crosssectional, multicenter study. Using 2008 your first college year yfcy survey data from the cooperative institutional research program at the higher education research institute at ucla, two scales are built and testedone measuring social. The underlying theory is built around a series of mathematical formulas that have parameters that need to be estimated using complex statistical algorithms. A narrative overview of the history, theoretical concepts, test theory, and irt is provided to familiarize the. Item response theory and classical test theory university of hawaii. Model linear non linear level test item assumption weak i. The frequently neglected and often misunderstood relationship between classical test theory and item response theory is discussed for the unidimensional case with binary measures and no guessing.
Whereas classical test theory focuses on the test as a whole, item response theory shifts its focus to the individual items questions themselves. Jul 15, 2015 item response theory is a general statistical theory about examinee item and test performance and how performance relates to the abilities that are measured by the items in the test. Classical test theory an overview sciencedirect topics. The aim of this study is to introduce the jmetric program which is one of the open source programs that can be used in the context of item response theory and classical test theory. The entire educational system is today highly concerned with the. Chapter 8 the new psychometrics item response theory. Although different models of ctt are based on slightly different sets of assumptions, all models share a fundamental premise postulating that the observed score of a person on a test is the sum of two unobservable components, true score and.
Classical truescore theory common factor theory not discussed in detail in this presentation. This study compared classical test theory ctt and item response theory irt. Instead of assuming all questions contribute equivalently to our understanding of a students abilities, irt provides a mo. These measurement theories offer certain advantages over ctt, but they are more complex and depend on stronger assumptions. Item response theory another branch of psychometric theory is the item response theory irt. Item response theory irt appears to be the currently prevailing paradigm within the psychometric theory. Demonstrating the difference between classical test theory. To provide comparisons and a worked example of item and scalelevel evaluations based on three psychometric methods used in patientreported outcome development classical test theory ctt, item response theory irt, and rasch measurement theory rmtin an analysis of the national eye institute visual functioning questionnaire vfq25. Part of theinstructional media design commons, and thestatistics and probability commons. Aug 19, 2017 for the love of physics walter lewin may 16, 2011 duration.
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