, Volume 62, Issue 3, pp 393–409 | Cite as

Rasch's model for reading speed with manifest explanatory variables

  • Margo G. H. Jansen


In educational and psychological measurement we find the distinction between speed and power tests. Although most tests are partially speeded, the speed element is usually neglected. Here we consider a latent trait model developed by Rasch for the response time on a (set of) pure speed test(s), which is based on the assumption that the test response times are approximately gamma distributed, with known shape parameters and scale parameters depending on subject “ability” and test “difficulty” parameters. In our approach the subject parameters are treated as random variables having a common gamma distribution. From this, maximum marginal likelihood estimators are derived for the test difficulties and the parameters of the latent subject distribution. This basic model can be extended in a number of ways. Explanatory variables for the latent subject parameters and for the test parameters can be incorporated in the model. Our methods are illustrated by the analysis of a simulated and an empirical data set.

Key words

reading speed tests Rasch model explanatory variables 


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Copyright information

© The Psychometric Society 1997

Authors and Affiliations

  • Margo G. H. Jansen
    • 1
  1. 1.University of GroningeneThe Netherland

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