Nbook item response theory and classical test theory in individual change assessment

Demonstrating the difference between classical test theory. This approach views ctt as a very general version of irt, and the commonly used irt models as detailed elaborations of ctt for special purposes. Item reponses theory ctt testoriented indices like reliability are groupspecific scores are testspecific contribution of item measured using other items e. Kline 2005 suggests ctt is known for development of some excellent psychometrically sound scales, founded by charles spearman around 1904. Whereas classical test theory focuses on the test as a whole, item response theory shifts its focus to the individual items questions themselves. It is a theory of testing based on the relationship between individuals performances on a test item and.

An ncme instructional module on comparison of classical. 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. In addition, irt has had a big impact on psychology by making possible several tools that would be difficult to create without irt. An ncme instructional module on comparison of classical test. Another branch of psychometric theory is the item response theory irt. Individual change assessment can be conducted using either the. According to classical test theory, if the observed variance of a test is 50 and the true variance is 40, what is the estimated reliability of the test. The following demonstrates a simulated dataset of 20 students true scores and their raw scores on a 10item test. Classical test theory and item response theory can be useful in providing a quantitative assessment of items and scales during the content validity phase of patientreported outcome measures. The classical theory assumes that each individual has a true score which. 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.

An empirical comparison of item response theory and. The theory and practice of item response theory methodology in the social sciences. The example was a 15item test with a sample size of 600 examinees eighthgrade level. The conceptual foundations, assumptions, and extensions of the basic premises of ctt have allowed for the development of some excellent psychometrically sound scales. The theory and practice of item response theory methodology.

We give an account of classical test theory ctt in terms of the more fundamental ideas of item response theory irt. Classical test theory vs item response theory by chris. 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. Educational and psychological measurem june 1998 v58 n3. Comparison of classical test theory and item response. Applying item response theory modeling in educational research. Therefore, its main purpose focuses on establishing the individuals position on that continuum. However, little empirical evidence is available to support the alleged superiority of irt in. Classical test theory ctt and item response theory irt ctt and its use in test analysis as the name would imply, classical test theory ctt is one traditional way of understanding test scores. Comparisons between classical test theory and item. Item response theory irt is a latent variable modeling approach used to minimize bias and optimize the measurement power of educational and psychological tests and other psychometric applications. Instead of testing the dimensionality of the test or questionnaire first, itemtotal. Oct 20, 2012 demonstrating the difference between classical test theory and item response theory using derived data. This study compared classical test theory ctt and item response theory irt.

This reflects that an instruments reliability may change depending on the. Classical test theory ctt comprises a set of concepts and methods that provide a basis for many of the measurement tools currently used in health research. Researchers have been optimistic about the possible advantages of using irt rather than ctt in change assessment. Item response theory and health outcomes measurement in the.

Irt is an example of what psychologists call a latent trait. Educational and psychological measurem june 1998 v58 n3 p357. 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. 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. Classical test theory ctt and itemresponse theory irt are testing item assessment approaches. Researchers should justify their evaluation method and consider the intended audience.

Georg rasch 1960 published a book describing several item. Item response theory irt has a number of potential advantages over classical test theory in assessing selfreported health outcomes. Classical psychometric test theory ctt aims at studying the reliability of a realvalued test score variable measurement, test that maps a crucial aspect of qualitative or quantitative observations into the set of real numbers. An introduction to polytomous item response theory models. Irt has been vigorously researched by psychometricians, and numerous books and articles. The item loglikelihood surface for two and threeparameter item characteristic curve models. The specific irt approach used is the oneparameter rasch. Item response theory irt, also known as latent trait theory or modern mental test theory.

When changes occur in either item difficulty or person ability, the probability. Item response theory provides powerful analytical tools that, even in their most basic applications, can be a valuable. Irt models yield invariant item and latent trait estimates within a linear transformation, standard errors conditional on trait level, and trait estimates anchored to item content. Comparing classical test theory and item response theory. The assumptions and concepts underlying ctt are discussed. May 31, 2015 classical test theory ctt and item response theory irt are testing item assessment approaches. Classical test theory and item response theory provide useful methods for assessing content validity during the early development of a pro measure. Using classical test theory, item response theory, and rasch.

Classical test analysis applied measurement associates. An empirical comparison of item response theory and classical test theory spela progar1 and gregor socan2 1mirna pec, slovenija 2university of ljubljana, department of psychology, ljubljana, slovenia abstract. Examination of person measurements estimates and the person. Patientsreported outcomes pro are increasingly used in clinical and epidemiological research. The theory and practice of item response theory by r. Item response theory has had a significant impact in psychology by allowing for more precise methods of assessing properties of tests compared with classical test theory. True t or f cross cultural fairness in testing has always been a critical factor in the development of tests. Item response theory irt vs classical test theory ctt. 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. Classical test theory ctt, also known as the true score theory, refers to the analysis of test results based on test scores. Comparison of classical test theory and item response theory in individual change assessment. Ctt is thought to be classical in that it is wellestablished, having resisted the erosion of time muniz, 2003, p.

Kline 2005 suggests ctt is known for development of some excellent psychometrically sound. Demars in her book chapter classical test theory and item response theory still. Item response theory requires several items so that there is adequate opportunity to have a sufficient range for levels of item difficulty and person attribute. Comparisons between classical test theory and item response. Comparison of classical test theory and item response theory. Demonstrating the difference between classical test theory and item. 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. Classical test theory ctt and itemresponse theory irt classical test theory ctt and itemresponse theory irt are testing item assessment approaches. Classical test theory vs item response theory by chris allred.

Item response theory is a statistical theory about items, test performance and abilities that are measured by items. Individual change assessment can be conducted using either the methodologies of classical test theory ctt or item response theory irt. 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. Jun 28, 2009 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. Demonstrating the difference between classical test theory and item response theory using derived data. Classical test theory is a body of related psychometric theory that predict outcomes of psychological testing such as the difficulty of items or the ability of testtakers.

The assessment of individual change in clinical contexts can be done using either the methodologies of classical test theory ctt or item response theory irt. An empirical comparison of item response theory and classical. Confirming diagnosis baselines measuring progress feasibility for discharge program eval. Item response theory irt models, in their many forms, are undoubtedly the. A fourth, and final shortcoming of the classical test theory is that it is test oriented, rather than item oriented. A comparison of individual change using item response theory and sum scoring on the. 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. Item response theory industrialorganizational psychology. The international journal of educational and psychological assessment, 1, 111 22 23. Item response theory irt is all about your performance on an exam, and how it relates to individual items or questions on a test.

A comparative study of classical theory ct and item. An application of item response theory to psychological. Ctt focuses on total test score individual items are not considered but their summary sum of responses, average response, or other quantification of overall level is the datum on which classical test theoretic constructs operate. An assessment that is done with the intent of causing positive change in the clients health and well being. Item response theory irt not covered in this lecture.

In this sense, classical test theory ctt has been extensively serving the testing field for about 100 years. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This is particularly important when fieldtesting a measuring instrument. 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. Model linear non linear level test item assumption weak i. This study aimed to examine the quality of both individual items and overall test construction of the test of proficiency in korean topik by applying classical test theory and item response. Comparison of classical test theory and item response theory in individual change assessment ruslan jabrayilov, wilco h. Classical test theory as a first order item response. Of course, over time, abilities may change because of instruction and other factors, but at the time of an assessment. Methodological issues regarding power of classical test. An exception could be the itemtotal correlation or splithalf versions of these e. Ctt approaches are familiar to most clinicians and are therefore widely used, but irt methods are also gaining popularity. In other words, classical test theory cannot help us make predictions of how well an individual or even a group of examinees might do on a test item. 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 theory in individual change assessment article in applied psychological measurement 408 august 2016 with 293 reads how we measure reads. Irt may be regarded as roughly synonymous with latent trait theory. 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 ctt approaches to psychometric measurement are familiar to. 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. Trait true score observed score classical test theory. 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. Basics of classical test theory california state university. Test theory and item response theory in individual change assessment. Overview of classical test theory and item response theory.

Designed for researchers, psychometric professionals, and advanced students, this book. Applying item response theory modeling in educational research daitrang le iowa state university follow this and additional works at. Part of theinstructional media design commons, and thestatistics and probability commons. An application of item response theory to psychological test. Generally speaking, the aim of classical test theory is to understand and improve the reliability of psychological tests classical test theory may be regarded as roughly synonymous with true score theory.

Comparisons between 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. Depending on the particular type of measure and the specific circumstances, either one or both approaches should be considered to help maximize the content validity of pro measures. Eric ed466779 classical test theory and item response. A primer on classical test theory and item response theory. Using classical test theory, item response theory, and. The item response theory irt, also known as the latent response. 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. The ctt and irt were compared across two samples and two forms of test on their item difficulty, internal consistency, and measurement errors. We propose here that item response theory analyses complements the basic ctt techniques presented in janssen and meier 20. Secondly, classical test analysis employs relative simple mathematical procedures and.

Comparison of classical test theory and item response theory in. Emons, and klaas sijtsma applied psychological measurement 2016 40. Item responses can be discrete or continuous and can be dichotomous and the item score categories can be ranked or non ranked. Classical test theory spearman, 1904, novick, 1966focuses on the. Based on nonlinear models between the measured latent variable and the item response, item response theory irt enables independent. Aside from determining the reliability of a test score variable itself ctt allows answering questions such as. Both classical test theory sum scores and item response theory estimates measure the same underlying dimension, but differences in the two scales may lead one to be more preferential than the other in interpreting data. 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. Two main types of analytical strategies can be found for these data. First, when compared to item response theory models, analyses can be performed with smaller representative samples of examinees. It was found in the study that 1 irt estimates of item difficulty do not change. Mismatch between individual ability and test difficulty can further. Item response theory columbia university mailman school of. Item response theory and health outcomes measurement in.