When power tests include a time limit, it is important to assess the possibility of "speededness" for examinees. Research on differential speededness in the past has included looking at gender and ethnic subgroups in the United States on paper and pencil tests. The needs of a global audience necessitated, and the availability of computer…

The author considers a latent trait model for the response time on a (set of) pure speed test(s), the multiplicative gamma model (MGM), which is based on the assumption that the test response times are approximately gamma distributed, with known index parameters and scale parameters depending on subject ability and test difficulty parameters. Like…