L. L. Thurstone

An internal consistency check for scale values determined by the method of successive intervals

The method of successive intervals is a psychological scaling procedure in which stimuli are classified into successive intervals according to the degree of some defined attribute which they are judged to possess. A psychological continuum is defined and the scale values are then taken as the medians of the distributions of judgments on the psychological continuum. It is assumed that the distributions of judgments for each stimulus are normal on the psychological continuum as defined.An internal consistency check indicates that the cumulative distributions of empirical judgments for the various stimuli can be reproduced by means of a limited number of parameters with an average error that compares favorably with that usually reported for paired comparison data. Furthermore, the scale values obtained by successive interval scaling, for the data reported, are shown to be linearly related to those obtained by the method of paired comparisons.

The perceptual factor

A further study of the perceptual factor, previously isolated in a factor analysis of a battery of fifty-six tests, is made in a manner designed also to determine whether the same seven primaries would be found in a different population of subjects and with another battery of tests. The tests are described, and the results of the analysis are given in detail. Much attention is given to the matter of the orthogonality of primary factors and to their psychological meaningfulness.

Note on a reanalysis of Davis' reading tests

Correlation data on nine reading tests originally analyzed by Frederick B. Davis by the principal axes method are reanalyzed by Spearmans uni-dimensional method. It is concluded that a single common factor (reading ability) accounts for the correlations among the tests with residuals remarkably small in view of the fact that the tests were designed to test nine supposedly different skills. Three of the tests showed additional specific variance not attributable to the common factor.

The dimensions of temperament

The correlations among the thirteen personality scores yielded by the Guilford schedule for factors STDCR, and the Guilford-Martin schedules for factors GAMIN, and O, Ag, and Co, as reported by Lovell, were factored by the centroid method. The purpose was to see how many factors were represented by the thirteen scores; therefore the test reliabilities were used in the diagonal cells. It was found that the scores represent not more than nine linearly independent factors. The orthogonal factor matrix was rotated to oblique simple structure. Seven of the oblique factors were given tentative interpretation. Two factors were regarded as residual factors because of the small variance which they represent. The seven factors have been named Active, Vigorous, Impulsive, Dominant, Stable, Sociable, and Reflective.

The prediction of choice.

This paper is concerned with a central concept in social measurement such as opinion polls, the measurement of attitudes, the prediction of political elections, the measurement of moral values, the measurement of consumer preferences, the measurement of utility, and the measurement of aesthetic values. The concept is that of the discriminal dispersion and its interesting effects in the prediction of choice.

The Absolute Zero in Intelligence Measurement

The object of this paper is to describe a discovery concerning the variability of intelligence by which it is possible to locate its absolute zero. The discovery will be described with four implications, namely, (i) two laws of variability of intelligence, (2) determination of the absolute zero of test intelligence, (3) the construction of a true mental growth curve which has not hitherto been possible, and (4) determination of the age at which test intelligence begins.

Ability, motivation, and speed

The relations between ability, motivation, and speed in a mental task are represented by a psychometric surface. Ability of a subject is defined as the degree of difficulty for which the probability is 1/2 that he will complete the task in infinite time. Motivation affects the rate at which mental work is done, but not the altitude of performance. Suggestions towards experimental work are made.

A new rotational method in factor analysis

A new rotational method, particularly appropriate when a positive manifold can be assumed, is presented in theory and in computational detail. It is applied to a five-dimensional factorial matrix in which a simple configuration is known to exist. The new technique is much more efficient in yielding the simple configuration than are the methods formerly used. Landahls transformations can be combined with this method to advantage.

Experimental study of simple structure

A battery of thirty-six tests was given to a group of high-school seniors. The factorial analysis reveals essentially the same primary factors that were found in previous studies. The test battery reveals a simple structure.

Current misuse of the factorial methods

Papers involving factorial methods appearing in current literature often misuse factorial methods. These meaningless results are reached because of neglect of certain conditions basic to factor theory. The conditions are:(1)The number of basic factors must be smaller than the number of tests.(2)The diagonals of the correlation matrix must be regarded as unknown.(3)The axes must be rotated into a simple configuration.(4)Each factor must be overdetermined by appearance in several tests.(5)Tests should have simple factorial composition.