The Item Response Theory framework encompasses a wide range of psychometric methods and mathematical models (latent trait models) to study individual responses to items defining a measurement instrument (multi-item scales such as questionnaires or tests) that is used to assess a specific construct ...

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Internal consistency and other item analyses

Is it appropriate to run internal consistency and other item analyses on a test that has questions with different response formats. To be clearer, all questions have a likert response, but some are 5 ...
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BIC in Item Response Theory Models: Using log(N) vs log(N*I) as a weight

In IRT software packages and in the literature it is common to calculate the BIC as $$ \mathrm{BIC} = -2 \cdot \mathrm{logLik} + \log(N)\mathrm{Npars} $$ where $N$ is the number of rows in wide ...
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35 views

Questions regarding interpretation of item parameters: inconsistent results between classical item analysis and item response analysis

I was not trained as a psychometrician, so my questions may be concept-related. If you know different resources, books, or articles that can clear my confusions, please let me know. Thank you very ...
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55 views

Is it possible to do IRT distractor analysis using R?

I've been using the mirt package to analyse a few response matrixes I have through IRT. However, every time I need to perform distractor analysis, I end up having ...
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119 views

Questions Regarding Item Response Models – the 3PL model vs. the mixture of 2PL and 3PL model

I currently work on an item analysis for an assessment. The assessment consists of 25 multiple-choice questions. Each question has 4 choices with one correct answer. I used different IRT models to ...
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72 views

Item discrimination of poorly targeted items

In test theory, it appears to be widely recognized that very "easy" or "very difficult" items, relative to the ability of the sample of respondents, will have deflated correlations with the rest of ...
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How to calculate the parameter value for a test with Item Response Theory?

Given a set of responses to a test with multiple choice I wish to analyse it with Item Response Theory: wikipedia on IRT. I am planing to use the 3PL (3 parameters) in the Item response function. How ...
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Is a representative sample necessary to assess construct validity?

To generalize results to a greater population, a representative sample is necessary. In developing a psychometrically valid instrument, via confirmatory factor analysis or item response theory, we are ...
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124 views

Misfitting of drift rate in Wiener model

In a binary-decision experiment, the accuracy and response time of some subjects were recorded. My goal is to fit a Wiener model to response time and accuracy data. The binary experiment has three ...
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16 views

Extracting latent factor from ranking data

I want to construct a model to link between a set of quantitative engineering parameters (e.g. Sm, Ra) of 9 material samples to a set subjective qualitative rankings of 6 perceived attributes, e.g. ...
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29 views

Recode Binary to scale Variables

I'm looking to find information to recode a set of dichotomous response variables to preferable a 1-5 scale. I have several response variables which when combined with PCA clearly depict certain ...
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1answer
130 views

What is the statistic to calculate Cronbach's alpha for Polytomous items in R

Does anyone know, what is the function which can calculate Cronbach's alpha for polytomous items with different categories in R? Thank you
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65 views

Itemfit to IRT model with missing data

I have matrix of dichotomus correct/false answers with many random missing data. (The data comes from an ability test where questions were randomly drawn from an item bank.) I am trying to find out ...
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38 views

Cut Score Determination in IRT

Cut score or cut point is a minimum achievement or ability that examinees should get in order to get a 'Pass'. In CTT, MCQ scoring in the form of percent-correct scores are applied. Let say we ...
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22 views

Validity in IRT Style

From my reading, I found that IRT generally provides more sophisticated information. Therefore, in regards of unidimensional 3PL IRT model, how should I report the finding about validity in ...
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30 views

Reading recommendations for psychometric refinement

a research project turned up a large number of survey instruments on a specific topic. There is a great deal of conceptual item overlap in these instruments, but they do differ in some key ways, ...
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48 views

Comparisons of confirmatory and exploratory model in IRT

I am trying to decide whether a theoretically derived (i.e. confirmatory) IRT model fits the data better than some parsimonious (i.e. exploratory) IRT model. Specifically, I have 14 binary indicators ...
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39 views

Likert scale survey student response independence

We administer a confidence survey (likert scale) comprising of 30 items and have conducted PCA to examine dimensionality, item independence and the like. We also conduct student interviews to assess ...
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2answers
335 views

Reliability in IRT Style

Reporting 'reliability' in IRT is more to 'informations' obtained and a bit different from a classical way using such as Cronbach alpha and KR20. Therefore, how to report the test reliability in ...
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25 views

Item Information Distorting Scale

I'm refining a psychometric questionnaire and working to estimate (2PL) IRT parameters for the items in order to score the items. It's a small scale consisting of 5 questions. The MAP and VSS-1 ...
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33 views

As a rule of thumb, difference in amount of administered items: classically scored vs adaptive (irt-based) tests?

I am thinking of developing a new adaptive test. One of the main goals is to shorten existing, classically scored tests. Is there a rule of thumb about how many items are needed to administered ...
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55 views

Understanding and applying Item Response Theory

In the process of designing a quiz application that can assess the student for understanding of a particular concept, I came across Item Response Theory. I have absolutely no clue whether applying ...
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51 views

Are there local maxima in the standard 2-pl model or is there proof that there aren't?

I'm looking to use iterative logistic regression to find the parameter values of the 2 pl model: $ P = \sigma(\alpha_{i} (\theta_{s} - \beta_{i})) $ where $ \sigma(x) = \frac{1}{1+e^{-x}} $ I know ...
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87 views

Latent Class Analysis vs Rasch Analysis

I was wondering if anybody could explain the core, philosophical/conceptual differences between Latent Class Analysis and Rasch Analysis. I'm not necessarily referring to the exact mathematical ...
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1answer
35 views

The probability of a student getting a given question correct and the associated uncertainty (Item response theory)

I'm doing some statistics on multiple choice test scores (with item response theory, (http://en.wikipedia.org/wiki/Item_response_theory). I want to know the probability that a student with a certain ...
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356 views

Item Response Theory vs Confirmatory Factor Analysis

I was wondering what the core, meaningful differences are between Item Response Theory and Confirmatory Factor Analysis. I understand that there are differences in the calculations (focusing more on ...
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107 views

IRT how to graph the Item Information Function [closed]

Following the Stata Manual - Item–response theory (IRT) models' example 28g — One-parameter logistic IRT (Rasch) model: use http://www.stata-press.com/data/r13/gsem_cfa , clear gsem (MathAb -> ...
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169 views

How to fit Graded Response Model with lme4::glmer

Thanks to Rijmen et al.(2003), we can fit GRM to the data with lme4::glmer. I think Rasch model is straightforward, with ...
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101 views

Longitudinal data format in WinBUGS or OpenBUGS, different number of items per time point

I am working with longitudinal data, where there are a different number of "items" per time point. I am working with the MCMCdynamicIRT1d function in ...
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141 views

Interpreting discrimination values in IRT polytomous (grm) models. Are there any cut-offs or anchors?

I am working on a project that is looking at the discriminative properties of 6, 5-point Likert items in a scale. I am using the ltm package in R to examine this within a item response theory (irt) ...
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154 views

How to obtain Item Information Curves for the Partial Credit Model?

I have estimated a Partial Credit Model in Stata following Zheng, X. and Rabe-Hesketh, S. (2007) "Estimating parameters of dichotomous and ordinal item response models using gllamm". I'd like to ...
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95 views

Multigroup Longitudinal Item Response WinBUGS OpenBUGS

I was able to fit the Longitudinal IRT model in Winbugs for an ordinal response by extending the BUGS code I took from the paper by Curtis in JSS http://www.jstatsoft.org/v36/c01/paper/ However, I am ...
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172 views

Implementing nominal model from Polytomous Item Response Theory

I am attempting to map out the probabilities of observing different categories given different person ability using the Nominal Model. From the handbook of Polymous Item Response Theory 2010, the ...
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413 views

Longitudinal item response theory models in R

I'm trying to fit longitudinal item response theory (IRT) models in R. I have a test that was administered at multiple measurement occasions. I'd like to examine individuals' growth curves of factor ...
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224 views

Is it possible to fit a Graded Response Model in Stata?

I've been reading about Item Response Theory during the past few weeks and I'd like to use it to examine how my scales are functioning. The response categories are ordinal. If I understood well, the ...
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47 views

Item Response Theory alternatives

What are other approaches than Item Response Theory to model learning of students in standardised tests?
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20 views

Datasets for exploring Cognitive Diagnosis Modelling [closed]

I recently became interested in Cognitive Diagnosis Modelling, which classifies respondents to skill profiles based on their responses and a hypothesized relation between skills and items (Q- or ...
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88 views

BUGS/JAGS for Nominal Response Model

I am a beginner with BUGS/JAGS and I was hoping to gather the opinion of you, experts. I am trying to implement a Nominal Item Response Analysis (Polytomous, not ordered, like a multiple-choice exam) ...
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430 views

How to check goodness of fit for a graded response model in R

I am using the grm function in the ltm package in R. There is no function to check the goodness of fit of the output. How can I ...
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1answer
238 views

Mixing dichotomous and polytomous items in one test

I have to evaluate a test paper which contains both dichotomous and polytomous items. I am currently using R. But in R IRT models for scoring of dichotomous and polytomous items are different and I ...
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161 views

Item reliability or fit in IRT-based adaptive tests?

My background is in machine learning and statistics, but I am relatively new to psychometrics and testing. Nearly all of the literature I've found on item reliability refers to Chronbach's alpha or ...
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73 views

Change in output depending on mirt version

I have a matrix which I'm trying to run through the mirt function of the mirt package: ...
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41 views

Inferring testlet structure in item response theory

Is it possible to infer the testlet structure in a set of items using item response theory? Specifically, I've created a lot of variations on the story recall task, each variation being scored on 25 ...
2
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1answer
241 views

How can I handle missing values when fitting IRT model?

I am conducting a study for analyzing male involvement in Family planning. It is of interest to develop an index for the involvement of male. I am currently having difficulties fitting an IRT model ...
2
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1answer
94 views

Calculating the space/distance between scale points (IRT)?

I am working with a seven item Likert Scale (1, 2......6, 7) for a classroom management. How can I calculate the distance between these seven scale points? This is for instrument reliability ...
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Comparing the Goodness of fit of two polytomous set of items not nested

I'm working on two identical set of items that only differ in their frequency-of-occurence dimension (in the first is max.7 while in the second is max.4). They are both fit with the Generalised ...
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230 views

Using Ltm package to calclate 3PL some lines of data seem to go missing

I am hoping someone can help with the following: I have been trying to use the ltm package in R to get person fit estimates using a 3PL model. The problem I have been having is that I start off ...
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1answer
201 views

Machine learning with trinomial features

I have 100,000 students who have each answered some multiple choice questions. Given their performance I want to work out what the chances are of a particular student answering the next question ...
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1answer
164 views

Computationally singular error using MIRT package

We've got a 524*40 data frame of responses to a likert-type scale questionnaire (7 response categories on 40 items). We want to do exploratory multidimensional IRT using the MHRM method to identify ...
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129 views

Applications of Item Response Theory

As far as I know, item response theory is mainly used within psychology to analyse survey data, personality questionaires or in educational setting. Are there other areas (possibly outside of ...