A simple guide to the item response theory irt and rasch. Item response theory irt has moved beyond the confines of educational measurement into assessment domains such as personality, psychopathology, and patientreported outcomes. Currently, standardized tests are widely used as a method to measure how well schools and students meet academic standards. This entry discusses some fundamental and theoretical aspects of irt and illustrates these with worked examples. How can internal consistency reliability of a test and of individual test items be quantified in item response theory models. Jan 08, 20 after several previous posts introducing item response theory irt, we are finally ready for the analysis of a customer satisfaction data set using a rating scale.
University of groningen applications of item response theory. Designed for researchers, psychometric professionals, and advanced students, this book clearly presents both the howto and the why of irt. It provides a powerful means to study individual responses to a variety of stimuli, and the methodology has been extended and developed to cover many different models of interaction. Responses to these types of items have been scored using a number of methods models e. Mar 18, 2017 drawing on the work of internationally acclaimed experts in the field, handbook of item response theory, volume two. Item response theory statistical methods training course. This volume presents a wideranging handbook to item response theory and its. Item response theory irt is used in the design, analysis, scoring, and comparison of tests and similar instruments whose purpose is to measure unobservable characteristics of the respondents. Skrondal and rabehesketh 2004 constitute a general class of models suitable for the analysis of multivariate data. In fact, the term item characteristic curve, which is one of the main irt concepts, can be attributed to ledyard tucker in 1946. They have grown from negligible usage prior to the 1980s to almost universal usage in largescale assessment programs. The next two sections explain the formulations of the rasch model and the twoparameter model.
Jan 10, 2017 this is the first of a series of powerpoints presented at a catirt workshop at the university of brasilia in 2012. In its simplest form, item response theory posits that the probability of a random person j with ability. Item response theory is used to describe the application of mathematical models to data from questionnaires and tests as a basis for measuring abilities, attitudes, or other variables. Linear versus models in item response theory roderick p.
There are occasional hints at the rst and the fourth, leaving the others largely untouched. Drawing on the work of internationally acclaimed experts in the field, handbook of item response theory, volume two. But, the presence of a strong first principal component in customer satisfaction ratings is much a. In the decade of the 1970s, item response theory became the dominant topic for study by measurement specialists. I know i can resort to classical test theory, cronbachs alpha, and other measures, but is there a way to characterize reliability within irt. This book is combined with a web site to allow the reader to acquire the basic concepts of item response theory without becoming enmeshed in the underlying mathematical and computational complexities.
This limits the implementation of the model in various applications and further prevents the development of other types of irt models that offer. Sample size requirements for estimation of item parameters. Models, of course, are never true, but fortunately it is only necessary that they be useful. Jan 01, 2009 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. Item response theory irt models, in their many forms, are undoubtedly the most widely used models in largescale operational assessment programs. This limits the implementation of the model in various applications and further prevents the development of other types of irt. An introductory 3day course introducing item response theory measurement models applied to psychological and educational data. 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. Introduction latent variable models bartholomew and knott 1999. Mcdonald macquarie university a broad framework for examining the class of unidimensional and multidimensional models for item responses is provided by nonlinear factor analysis, with a classification of models as strictly linear, linear in their coefficients, or strictly nonlinear.
But, the presence of a strong first principal component in customer. University of groningen a comparison between factor. Specifically, irt models are mathematical equations describing the association between subjects levels on a latent variable and the probability of a particular response to an item, using a nonlinear monotonic function. The theory and practice of item response theory rafael. From a draft of item response theory for psychological research. Unidimensional item response models are used to model latent abilities and specific item characteristics. It provides a powerful means to study individual responses to a variety of stimuli, and the methodology has been extended and. Drawing on the work of internationally acclaimed experts in the field, handbook of item response theory, volume one. Pdf an introduction to item response theory and rasch. As a result, measurement issues have become an increasingly popular topic of study. Seavey of heinemann educational books for first suggesting that i do a small book on item response theory, which resulted in the first edition of this book in 1985.
Item response theory irt model differs in terms of the number of parameters contained in the model. Multiple cateogry item analysis and test scoring using item reponse theory computer. This is the first of a series of powerpoints presented at a catirt workshop at the university of brasilia in 2012. It provides an introduction to item response theory irt, tying it to classical test theory and describing some of the major irt models. This process is experimental and the keywords may be updated as the learning algorithm improves. Unfortunately, the few available textbooks are not easily accessible to the audience of psychological researchers and practitioners. Item information function and test information function iv. Irt and cat using concerto 3 days the psychometrics centre. Other names and subsets include item characteristic curve theory, latent trait theory, rasch model, 2pl model, 3pl model and the birnbaum model.
Rasch, 1960, irt has emerged relatively recently as an alternative way of conceptualizing and analyzing measurement in the behavioral sciences. Sep 03, 2016 item response theory item response theory irt refers to a family of latent trait models used to establish psychometric properties of items and scales sometimes referred to as modern psychometrics because in largescale education assessment, testing programs and professional testing firms irt has almost completely replaced ctt as method of. Item response theory irt is not only the psychometric theory underlying many major tests today, but it has many important research applications. Overview of classical test theory and item response theory. Carstensen in this chapter we illustrate the use of item response models to analyze data resulting from the measurement of competencies. Item characteristic curve in one to three parameter models iii. Item response theory, reliability and standard error. This first volume in a threevolume set covers many model developments that have occurred in item response theory irt during the last 20 years. The singleparameter logistic item response theory irt measurement model commonly known as the rasch model provides a theoretical base and a set of statistical tools to assess the suitability of a set of survey items for scale construction, create a scale from the items, and. Item response theory columbia university mailman school of.
Item response theory test theory item parameter item response theory model classical test theory these keywords were added by machine and not by the authors. Introduction to item response theory linkedin slideshare. Sample size requirements for estimation of item parameters in. University of groningen applications of item response. Evaluating the impact of multidimensionality on unidimensional item response theory model parameters s. Item response theory irt is used in a number of disciplines including sociology, political science, psychology, human development, business, and communications, as well as in education where it began as a method for the analysis of educational tests. Classic and emerging irt methods and applications that are revolutionizing psychological measurement, particularly for health assessments used to demonstrate treatment. In a few words, item response theory irt postulates that a examinee test performance can be predicted or explained by a set of factors called traits, latent traits, or abilities, and b the. Samejima, 1969 is one of the most popular polytomous item response theory irt models that are able to utilize all the information from each item. Item response theory and rasch models i tem response theory irt is a second contemporary alternative to classical test theory ctt. An r package for latent variable modeling and item. Sterken en volgens besluit van het college voor promoties. Irt can be multidimensional, and r is fortunate to have its own package, mirt, with excellent documentation r. Modern approaches to parameter estimation in item response theory l.
The first edition, with its accompanying software, was designed to give the reader access to the basic concepts of item response theory without having to do the tedious. But, the genesis of item response theory irt can be traced back to the midthirties and early forties. Chapter 8 the new psychometrics item response theory. Statistical tools presents classical and modern statistical tools used in item response theory irt. Item response theory is the study of test and item scores based on assumptions concerning the mathematical relationship between abilities or other hypothesized traits and item responses.
This document, which is a practical introduction to item response theory irt and rasch modeling, is composed of five parts. A gibbs sampler for the multidimensional item response model. Item response theory item response theory irt refers to a family of latent trait models used to establish psychometric properties of items and scales sometimes referred to as modern psychometrics because in largescale education assessment, testing programs and professional testing firms irt has almost completely replaced ctt as method of. Internal consistency reliability in item response theory. After several previous posts introducing item response theory irt, we are finally ready for the analysis of a customer satisfaction data set using a rating scale. It is used for statistical analysis and development of assessments, often for high stakes tests such as the graduate record examination. Item response theory has become an essential component in the toolkit of every researcher in the behavioral sciences.
The paper introduces the basic concepts of irt models and their applications. University of groningen a comparison between factor analysis. Without the work of these three individuals, the level of development of item response theory would not be where it is today. Nering and ostini, 2010, among which the graded response model grm. Current procedures for estimating compensatory multidimensional item response theory mirt models using markov chain monte carlo mcmc techniques are inadequate in that they do not directly model the interrelationship between latent traits. Over the last 30 years item response theory irt has essentially replaced traditional classical test theory approaches to designing, evaluating, and scoring largescale tests of cognitive ability. Responses to these types of items have been scored using a number of methodsmodels e.