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ACER ConQuest 4

Author(s): Adams, R.J, Wu, M.L, and Wilson, M.R. (2015)


ACER ConQuest 4 is a computer program for fitting both unidimensional and multidimensional item response and latent regression models. It provides data analysis based on a comprehensive and flexible range of item response models (IRM), allowing examination of the properties of performance assessments, traditional assessments and rating scales. ACER ConQuest 4 also offers wider measurement and research community analysis procedures based on the most up-to-date psychometric methods of multifaceted item response models, multidimensional item response models, latent regression models and drawing plausible values.


The ACER ConQuest Version 4 software includes:

  • Estimation of the Bradley–Terry–Luce (BTL) model for pairwise comparisons
  • A choice of marginal maximum likelihood or joint maximum likelihood estimation
  • Fitting of a multidimensional and multifaceted form of Bock’s nominal response model, including its special cases, the two parameter logistic (2PL) model and generalised partial credit model
  • Direct reading of SPSS system files
  • Output of results to SPSS or EXCEL files
  • A wide array of graphical outputs, including Wright maps and Wright predicted probability maps
  • Person fit and residuals
  • Latent variable path modelling
  • Mantel-Haenszel DIF estimates

The ACER ConQuest Version 4 has the following new features:

  • Implementation of multidimensional and multifaceted Bock model and generalised partial credit model (GPCM)
  • Addition of matrix variables
  • Matrix manipulation functions: compute, for, if and while commands to manipulate matrices
  • Functionality to create likelihood plots
  • Functionality to create information maps

ACER ConQuest 4 is initially available for download as a free 30-day trial. After downloading the trial, the following licences may be purchased via the ACER shop:

  • Student (Windows: $375; Mac: $300)
  • Standard (Windows: $750; Mac: $600)
  • Multiple Standard (per computer: Windows: $595; Mac $476)

The following licences require approval:

  • Instructor Licence (annually per course: Windows: $1500; Mac: $1200)
  • Extended Licence (annual, extensions subject to approval)

For technical support, please view the ACER ConQuest Forum or email

Author(s): Adams, R.J, Wu, M.L, and Wilson, M.R. (2015)