A general approach to confirmatory maximum likelihood factor analysis

We describe a general procedure by which any number of parameters of the factor analytic model can be held fixed at any values and the remaining free parameters estimated by the maximum likelihood method. The generality of the approach makes it possible to deal with all kinds of solutions: orthogonal, oblique and various mixtures of these. By choosing the fixed parameters appropriately, factors can be defined to have desired properties and make subsequent rotation unnecessary. The goodness of fit of the maximum likelihood solution under the hypothesis represented by the fixed parameters is tested by a large samplex ² test based on the likelihood ratio technique. A by-product of the procedure is an estimate of the variance-covariance matrix of the estimated parameters. From this, approximate confidence intervals for the parameters can be obtained. Several examples illustrating the usefulness of the procedure are given.This work was supported by a grant (NSF-GB 1985) from the National Science Foundation to Educational Testing Service.     

Predicting the Success of Freshman Engineers

An awareness and commitment rating was assessed for a freshman engineering class to determine whether this type of non-intellective measure could help improve the predictability of academic success. The total sample was broken into subsamples based on the interview condition of the student: staff interview; alumni interview; or no interview. The existence of a factor defined as awareness/commitment was supported. For the total sample a significant correlation was found, but at a very low level. For the subsample interviewed by staff, a correlation of .31 was determined. This relationship suggests the possibility of real usefulness for the admissions interview in identifying the factor of awareness and commitment, and thereby improving the prediction of academic success in a professional curriculum such as engineering.     

The role of the cs and avoidance period duration in discriminated avoidance conditioning

In an experiment investigating the effect of CS duration on discriminated bar-press conditioning, subjects were assigned to one warning period duration (1.5, 5.0 or 15.0 sec.) on the first day of avoidance training, and to one of the three durations on the second day of training. On each day avoidance behaviour was greatly influenced by the duration of the CS (warning) period, but the duration on day I had no effect on the second day's avoidance performance. Groups receiving no CS during training, although provided an avoidance contingency, showed little conditioning, but produced highly significant amounts of intertrial responding. In a second experiment, subjects receiving CS on day I were shifted to no CS on day II. Avoidance performance on day II was not significantly different from the day II performance of subjects in Experiment I having two training sessions with the CS present or absent on both days.