ConQuest

Generalized Item Response Modelling Software

ConQuest is a computer program developed at the Australian Council for Educational Research (ACER) for fitting item response and latent regression models. It provides a comprehensive and flexible range of item response models to analysts, allowing them to examine the properties of performance assessments, traditional assessments and rating scales. ConQuest also makes available, to the wider measurement and research community, the most up to date psychometric methods of multifaceted item response models, multidimensional item response models, latent regression models and drawing plausible values.

What are the models that ConQuest can fit?

ConQuest brings together in a single program a wide variety of item response models (including multidimensional models) and provides an integration of item response and regression analysis.

Rasch's Simple Logistic Model

Rating Scale Model

Partial Credit Model

Ordered Partition Model

Linear Logistic Test Model

Multifaceted Models

Generalized Unidimensional Models

Multidimensional Item Response Models

Latent Regression Models

How does ConQuest fit these models?

ConQuest produces marginal maximum likelihood MMLE estimates for the parameters of the models listed. The estimation algorithms used are adaptations of the quadrature method described by Bock and Aitken (1981) and the Monte Carlo method of Volodin and Adams (1995). The fit of the models is ascertained by generalizations of the Wright and Masters (1982) residual-based methods that were developed by Wu (1997).

Some applications of ConQuest

Performing item analysis

Examining differential item functioning

Exploring rater effects

Estimating latent correlations

Testing dimensionality

Drawing plausible values

Demonstration versions can be downloaded from www.acer.edu.au/quest

ACER ConQuest: Generalized Item Response Modelling Software … Rasch Measurement Transactions, 1999, 13:3 p. 711


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