SMABS 2004 Jena University
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European Association of Methodology

Department of methodology and evaluation research

Jena University

Contributions: Abstract

A comparison of latent trait models for speed tests with different distributional assumptions

Margo G.H. Jansen
University of Groningen
The Netherlands

Response times are considered relevant in a wide variety of psychological and educational measurement situations. In particular, the use of computers for test adminstration has opened the possibility to study observations that are not available in paper and pencil tests, such as the response times on individual items. Response times can be seen as achievement measures in their own right but also as explanatory variables for other types of test behavior.

We consider models for item- or test response latencies. Both the lognormal and the gamma distribution, can be viewed as suitable distributions for modelling continuous positive random variates. The extended Rasch model assuming gamma distributed response times is compared with a mixed regression model assuming lognormal distributed response variables. For fitting the lognormal mixed regression model standard multi-level modelling software can be used. A number of empirical examples are given.