The use of indices of speededness in tests is reviewed and three possible indices which derive from a model which assumes that rate of work is normally distributed is proposed. Each of these indices is seen as limited by the failure to adequately consider the correlation between speed and power, but they have the advantage that they are derivable…

A group of 21 students was tested under a time limit considerably shorter than should have been allowed. This report describes a tryout of a method for estimating the power'' scores that would have been obtained if the students had had enough time to finish. (Author/CB)

A more generalized error model for time-limit tests is developed. Model estimates are derived for right-attempted and wrong-attempted correlations both within the same test and between different tests. A comparison is made between observed correlations and their model counterparts and a fair agreement is found between observed and expected…

A method for estimating power scores is described. By way of illustration, it is applied to 21 students who were improperly timed on a standard test. Some empirical results are given in support of the estimation procedure. (Author)

The previous theoretical development of the Poisson process as a strong model for the true-score theory of mental tests is discussed, and additional theoretical properties of the model from the standpoint of individual examinees are developed. The paper introduces the Erlang process as a family of test theory models and shows in the context of…

The family of Weibull distributions was investigated as a model for the distributions of response times for items in computer-based criterion-referenced tests. The fit of these distributions were, with a few exceptions, good to excellent according to the Kolmogorov-Smirnov test. For a few relatively simple items, the two-parameter gamma…