Model based clustering of large data sets: Tracing the development of spelling ability

There are two main theories with respect to the development of spelling ability: the stage model and the model of overlapping waves. In this paper exploratory model based clustering will be used to analyze the responses of more than 3500 pupils to subsets of 245 items. To evaluate the two theories, the resulting clusters will be ordered along a developmental dimension using an external criterion. Solutions for three statistical problems will be given: (1) an algorithm that can handle large data sets and only renders non-degenerate clusters; (2) a goodness of fit test that is not affected by the fact that the number of possible response vectors by far out-weights the number of observed response vectors; and (3) a new technique,data expunction, that can be used to evaluate goodness-of-fit tests if the missing data mechanism is known. Research supported by a grant (NWO 411-21-006) of the Dutch Organization for Scientific Research.     

‘Peer review’ culture

A relatively high incidence of unsatisfactory review decisions is widely recognised and acknowledged as ‘the peer review problem’. Factors contributing to this problem are identified and examined. Specific examples of unreasonable rejection are considered. It is concluded that weaknesses of the ‘peer review’ system are significant and that they are well known or readily recognisable but that necessary counter-measures are not always enforced. Careful management is necessary to discount hollow opinion or error in review comment. Review and referee functions should be quite separate.     

Factor analysis and Psychometrika: Major developments

Papers on factor analysis appearing inPsychometrika reflect the initial efforts of the Thurstonians to reformulate psychology as a quantitative science. The Thurstonians' emphasis on the development of factor analysis as an exploratory methodology was not new with them but was taken from British statisticians and psychologists who preceded them, whose literature the Thurstonians otherwise tended to ignore. The Thurstonians' rejection of general factors and focus on rotation to simple structure reflected an attempt to avoid statistical artifact and to identify factors with psychological substance. Much of the literature on factor analysis inPsychometrika concerned solving technical problems in the exploratory factor analysis method. Factor analysis took a major shift in direction in the 1970's with the development of confirmatory methodologies, many of which now receive greater attention than the method of exploratory factor analysis, most of the problems of which are now resolved.     

A note on Roy's largest root

The name Roy's largest root and similar names are used in practice to label two different but functionally related statistics—one proportional to anF, and the other, a squared canonical correlation. This note presents the logic that leads to the two formulations, states which statistic some popular statistical packages use, and shows the possible source of this inconsistency in the original work of Roy (1953) and Heck (1960).     

Covariation assessment in rank order data

Two experiments were conducted to investigate how individuals assess covariation with rank order data. In both studies, subjects were given sets of rank order data, each set consisting of ten items ranked on two characteristics, and were asked to estimate the degree of relationship for each set. Contrary to previous research, subjects' estimates of covariation in this task were quite sensitive to actual levels of correlation in the data and remained unaffected by simple variations in the way rank order data were presented. More importantly, it appeared that this sensitivity to covariation was due likely to the use of a simple heuristic referred to here as the total discrepancy heuristic. These findings are discussed in terms of the availability of simple heuristics in rank-ordered versus other types of data and the consequences of using such heuristics in decision-making contexts.     

《心理学报》论文的引文统计与分析

运用文献计算学的原理,对《心理学报》６年论文所附引文进行了统计分析,定量地描述了该刊的引文量,自引量,类型,语种,年代等的分布,目的在于了解心理学领域核心期刊的引文状况的寻求我国心理学论文引用文献的一些规律及所反映的问题。     

The rowwise correlation between two proximity matrices and the partial rowwise correlation

This paper discusses rowwise matrix correlation, based on the weighted sum of correlations between all pairs of corresponding rows of two proximity matrices, which may both be square (symmetric or asymmetric) or rectangular. Using the correlation coefficients usually associated with Pearson, Spearman, and Kendall, three different rowwise test statistics and their normalized coefficients are discussed, and subsequently compared with their nonrowwise alternatives like Mantel'sZ. It is shown that the rowwise matrix correlation coefficient between two matricesX andY is the partial correlation between the entries ofX andY controlled for the nominal variable that has the row objects as categories. Given this fact, partial rowwise correlations (as well as multiple regression extensions in the case of Pearson's approach) can be easily developed.The author wishes to thank the Editor, two referees, Jan van Hooff, and Ruud Derix for their useful comments, and E. J. Dietz for a copy of the algorithm of the Mantel permutation test.     

Interrupted time-series analysis and its application to behavioral data

This paper uses a question-and-answer format to present the technical aspects of interrupted time-series analysis (ITSA). Topics include the potential relevance of ITSA to behavioral researchers, serial dependency, time-series models, tests of significance, and sources of ITSA information.     

"Perhaps it would be better not to know everything."

The advent of statistical methods for evaluating the data of individual-subject designs invites a comparison of the usual research tactics of the group-design paradigm and the individual-subject-design paradigm. That comparison can hinge on the concept of assigning probabilities of Type 1 and Type 2 errors. Individual-subject designs are usually interpreted with implicit, very low probabilities of Type 1 errors, and correspondingly high probabilities of Type 1 errors, and correspondingly high probabilities of Type 2 errors. Group designs are usually interpreted with explicit, moderately low probabilities of Type 1 errors, and therefore with not such high probabilities of Type 2 errors as in the other paradigm. This difference may seem to be a minor one, considered in terms of centiles on a probability scale. However, when it is interpreted in terms of the substantive kinds of results likely to be produced by each paradigm, it appears that the individual-subject-design paradigm is more likely to contribute to the development of a technology of behavior, and it is suggested that this orientation should not be abandoned.