Authors: Adams, R.J, Wu, M.L, Cloney, D., Berezner, A., and Wilson, M.R. (2020)..

Publisher: ACER   

ACER ConQuest 5 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 5 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.

Bibliographic reference:
Adams, R.J, Wu, M.L, Cloney, D., Berezner, A., and Wilson, M.R. (2020). ACER ConQuest: Generalised Item Response Modelling Software (Version 5.29) [Computer software]. Australian Council for Educational Research. https://www.acer.org/au/conquest

ACER ConQuest Version 5 software includes:

  • A choice of marginal maximum likelihood, joint maximum likelihood or Bayesian Markov Chain Monte Carlo (MCMC) estimation

  • With MCMC estimation, the ability to add random effects to the item response model

  • Implementation of multidimensional and multifaceted Bock model and generalised partial credit model (GPCM)

  • Estimation of the Bradley–Terry–Luce (BTL) model for pairwise comparisons

  • Direct reading of SPSS data files and CSV text files

  • Output of results to SPSS, EXCEL, CSV or other text files

  • A wide array of graphical outputs, including Wright maps, Wright predicted probability maps, likelihood plots and information maps

  • Person fit and residuals

  • Latent variable path modelling

  • Mantel-Haenszel DIF estimates

  • Powerful manipulation of matrix variables and control logic (if, while, do) for advanced modelling, including specifying custom design matrices or fitting iterative models.

  • Integration with R through the conquestr library

  • Advanced features, including the ability to impose new constraints on GPCM models, including imposing maximum and positive scores, as well as freely estimated variances through slope constraints.

To download the installer/trial version and/or purchase licence keys, please visit the ACER shop at:


Further information, queries and technical support:
For sales queries, please view the ACER ConQuest FAQ or email sales@acer.org.
For technical support, please email conquest@acer.org.