Jerome E. Doppelt

Estimation of the Differences Between WISC-R and WISC IQS

The purpose of the study was to estimate the magnitude of the differences between IQs obtained from WISC-R and those from the original WISC. The 1949 WISC and the 1974 WISC-R were reviewed to identify a common core of items. Regression equations were developed for the 1949 sample, by age level, to predict WISC IQs from the common core. These equations were then used to estimate the WISC IQs of those in the WISC-R standardization sample. In the age range 6½ to 15½ years, the Full Scale IQs on WISC-R were 4 points lower, on the average, than WISC IQs. The difference, however, varied with the particular IQ Scale (Verbal or Performance), age, and ability level.

The Evaluation of Pairs of Tests for Guidance Use

tered to the client for the purpose of revealing his strengths and weaknesses so that he may decide upon a career which will utilize his superior capacities and avoid, so far as possible, dependence upon those characteristics in which he is least able. Consequently, it is desirable to have tests which do not correlate very highly with each other, thereby measuring relatively independent traits. Another characteristic of importance in the selection of tests for this purpose is high reliability so that differences in scores shall be, so far as possible, true differences rather than accidental ones.

A Longitudinal Study of the Differential Aptitude Tests

I. Long Term Consistency of Measurement Assuming that a characteristic or trait is worth measuring in the first place, a question that may be asked is : &dquo;How well does present measurement predict a person’s rating on this variable in the future?&dquo; In effect, this question seeks to determine whether relative ability, in the characteristic measured, is independent of the many factors which may affect an indi-

Item Difficulty and Speed of Response

A recurrent problem in test construction is the determination of appropriate time limits for &dquo;power&dquo; tests. If too short a time is stipulated, the score will be appreciably affected by the subject’s speed. If the allotted interval is unduly generous, there results a less efficient use of time, frequently accompanied by an unhappy restiveness among the more rapid members of the group. Since speed in answering is known to be correlated with power scores obtained under unlimited time conditions, it is probable that a small degree of &dquo;speededness&dquo; will not seriously contaminate &dquo;power&dquo; scores. The conventional arrangement of items in order of ascending difficulty (descending p values) makes it likely that the slower, and generally less capable, subjects who fail to finish within the time limit will be deprived of the opportunity of answering only those items which offer little likelihood of adding to their scores.

Relative Efficiency of Seven Verbal Item Types

istic tested, the contribution of the item to the reliability of the scale, and the speed with which the item is answered. Many verbal tests have been published, and in these there appear a great variety of item forms. So far as the authors of this paper are aware, there are no published data which permit comparison of the virtues of different verbal item types. This paper reports the results of a study of seven types of items used to measure verbal intelligence. These comprise the parts of the Terman-McNemar Test of Mentallbility, Form C (1). Examples of each type follow: Part i-Information

Progress in the Measurement of Mental Abilities

different abilities. Users of tests have increasingly accepted the principle that multiple measurement is a more effective aid to evaluation and counseling than a single score. With this acceptance has also come recognition of the problems associated with multiple measurement. For such measurement to be effective it must necessarily be differential; that is, the abilities measured should be relatively independent. There obviously would be little point in getting different measures of essentially the same ability. Various techniques have been employed to achieve independence of measurement. Indeed, the development of these techniques has constituted an important advance in methodology. As an investigative technique, factor analysis is a