Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [rasch]

The Rasch model is used to model the relation between individual location (ability) on a latent trait and their probability of endorsing a dichotomous item, which is characterized by its difficulty, assuming all items are equally discriminative.

The Rasch measurement model is the simplest of the item response theory (IRT) family of measurement models. Due to the simplicity of the model, it allows smaller sample sizes to arrive at stable parameter estimates. The Rasch model will analyze data that are: 1) dichotomous (right or wrong), 2) polytomous (rating scale or partial credit items, and 3) many-faceted (e.g., raters, items, and students).

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Simulating responses to a test for item-response theory

I am developing an online assessment system and I need to calibrate the bank of questions but I do not have enough people to implement a pilot test. That is why I decided to simulate the responses of the question bank. I will use the Rasch model for…
Erika Hernández
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Classification with 3 groups, repeated measurements, missing values, more predictors than subjects

I am working on a classification problem with the following characteristics: Individuals belong to one of three groups. The groups are "somewhat ordinal": controls, subclinical and clinical group. Each individual is measured five times on each…
Stephan Kolassa
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What is the difference between a Rasch model and a mixed-effects logistic regression?

I've recently been learning about the Rasch model. Previously I've used various kinds of generalized regression, including linear as well as logistic and "vanilla" fixed-effects models as well as models with random effects. What I still haven't…
BrenBarn
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Assessing the fit of GLMM implementation of a Rasch model to binary data using lme4

I'd like to assess the fit of the kinds of models described by de Boeck et al (2011) (http://www.jstatsoft.org/v39/i12). They are GLMM implementations of Rasch family models, e.g.: all.1.NULL.Rasch <- glmer(score ~ -1 +…
Michael
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Is nested ANOVA model appropriate for analysing student performance on a pre/post test?

I am analyzing student performance on a pre/post test designed to assess gains for a week long high school biology curriculum on natural selection. After comparing pre/post performance using a variety of different metrics (test score, Rasch measure,…
mfernan5
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Pros/cons of estimating parameters for missing observations?

Some people are playing a game online. Every time a person plays, a new game board is generated randomly. On generation of a new board, the player can also choose a special weapon. (The choice of weapon does not affect the board generation.) Over…
Jack Tanner
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Appropriateness of Rasch for formative measurement models

I've spent several months thinking about the issue of whether or not it is appropriate to apply Rasch models to formative measurement models, and I'm looking to see whether anybody else has considered this issue, and what the answer is. People…
Ian_Fin
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Is there an R package which implements weighted maximum likelihood for Rasch models?

Is there a package in R which implements the weighted maximum likelihood method (Warm, 1996) for estimating the person parameters in Rasch Models?
Paul Illg
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Dealing with a partially pooled intercept in a Bayesian model

I have a multilevel logistic regression (Rasch), fit in JAGS. Specifically, $\text{logit} (P(\text{Win})) = \alpha_p + \gamma_w + \delta_{p,w}$ The prior on $\alpha_p$ is partially pooled, $\alpha_p \sim N(\mu_\alpha,\tau_\alpha)$, and the rest of…
Jack Tanner
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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 the test (item-rest correlations). One way of…
Erik
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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 calculations involved. I'm more interested in - why…
SimonsSchus
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What exactly is "requirements for fundamental measurement" for rasch model?

In this introduction of Rasch Model, it says "the Rasch model emphasizes the primacy of the requirements for fundamental measurement". What exactly does "requirements for fundamental measurement" mean? According to this site, fundamental measurement…
Aqqqq
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How can I estimate student abilities with a Rasch Model?

I have a dataset of test results. There are 400 students, and 100 items. I ran ltm::rasch in R, and I computed ability scores for each student, and difficulty scores for each item. I would now like to reuse this model. There is a method called…
djacobs7
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Consequences of violating assumptions about errors in IRT/Rasch based models

In the sorts of measurement models to which one might apply IRT models, including Rasch models, there is not thought to be an error associated with the latent variable. Rather, the latent variable is thought to cause indicators, which themselves…
Ian_Fin
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DIF (differential item functioning) and wanted structural heterogeneous ability of test

I'm calibrating an item pool which enables enables especially to measure different abilitylevels. The item pool is for an economy-achievementest. Therefore, a broad range of items is needed, which difficulty-levels scatters widely over the scale.…
Benzema
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