A post hoc correction procedure for systematic errors in time-sampling duration estimates

Numerous previous studies have shown that partial-interval sampling in direct observation systematically overestimates duration and underestimates frequency. Whole-interval sampling systematically underestimates both duration and frequency. This paper presents a post hoc method through which the systematic errors in duration estimates in partial-interval sampling and whole-interval sampling can be minimized.     

Psychopathology in anxiety disorders

Complaints of anxiety, often meetingDiagnostic and Statistical Manual of Mental Disorders, 3rd ed. (DSM-III), criteria for anxiety disorder, are among the most common problems presenting to health practitioners. In spite of the frequency of anxiety and anxiety disorders, little is known about the basic psychopathology of these conditions that would lead to the development of more efficient and effective treatments and possible preventive efforts. Recently, there has been an increase in research on the psychopathology of anxiety disorders from biological, psychological, and social perspectives. The National Institute of Mental Health's Clinical Research Branch sponsored a 2-day workshop of investigators representing diverse research approaches to discuss emerging issues and research practices within the anxiety disorders. Discussions centered on a review of the general areas of classification, phenomenology, and etiology. A selective summary of this workshop is presented along with recommendations for specific research directions.     

Forced classification: A simple application of a quantification method

This study formulates a property of a quantification method, the principle of equivalent partitioning (PEP). When the PEP is used together with Guttman's principle of internal consistency (PIC) in a simple way, the combination offers an interesting way of analyzing categorical data in terms of the variate(s) chosen by the investigator, a type of canonical analysis. The study discusses applications of the technique to multiple-choice, rank-order, and paired comparison data.This study was supported by the Natural Sciences and Engineering Research Council of Canada (Grant No. A7942). Comments on the earlier drafts from anonymous reviewers and the editor were much appreciated.     

卡车驾驶员速度估计研究

用速度知觉测试仪,对251名男性卡车驾驶员在四种实验条件下的速度估计准确性进行了测量。结果发现：安全组卡车驾驶员的速度估计准确性优于事故组卡车驾驶员,两者在低速条件下差异不显著,高速条件下差异显著;事故组卡车驾驶员的高估次数高于安全组卡车驾驶员,低速条件下两者不显著.高速条件下差异显著;事故多发组与安全组卡车驾驶员的速度估计准确性在高速及低速长距离条件下差异显著;速度及距离对速度估计准确性有显著影响,且两者之间存在显著的交互作用;年龄对速度估计准确性无显著影响。     

Comparisons of rats' choice behavior among three different radial-maze tasks

The present study compared rats' behavioral changes on three tasks on the radial-arm maze. In the free-choice task (0Fo/8Fr; no forced choice/eight free choices), rats performed efficiently with the simple response pattern of sequential adjacent-arm choices. In the two forced-choice tasks (3Fo/5Fr and 5Fo/3Fr), rats performed as efficiently as 0Fo/8Fr but showed no particular response patterns. The frequency of arm investigation was the highest in 5Fo/3Fr, and was higher in 3Fo/5Fr than in 0Fo/8Fr. The probability of correct rejection, avoiding re-entry to visited arms after investigation, was also higher in 3Fo/5Fr and 5Fo/3Fr than in 0Fo/8Fr. These results suggest that the rats could adjust their behavior to the task demands.     

Prediction accuracy of text recall: Ease, effort and familiarity

Prediction accuracy of text recall was studied in two experiments. Text characteristics (i.e., consistency and distinctiveness) were manipulated in Experiment 1, and familiarity with the reading-task in Experiment 2. The results were also analyzed and discussed in terms of easy processing (Experiment 1), and in terms of increased and more active processing (Experiment 2). Text characteristics did not affect prediction accuracy. However, being familiar with the reading-task led to good and long-lasting prediction accuracy. Thus, subjects reading a school-book text, instructed to learn the contents of it demonstrated reliable memory awareness, both for immediate recall and for delay of one week. It was also suggested that increased processing demands and active reading enhances prediction accuracy.     

Effects of diagnostic classification systems on clinical hypothesis-generation

In this study it was determined whether (a) classification as opposed to absence of classification has an effect on the quality of clinical hypotheses (b) the DSM-III-R and the CBCL have a different effect on the quality of clinical hypotheses, and (c) the potential difference between the DSM-III-R and the CBCL is moderated by the different number of syndromes identified by these systems. To investigate these questions, an experiment was conducted in which 86 clinicians generated hypotheses for six cases. The clinicians were divided into a DSM-III-R, a CBCL, and a control group. Of the six cases, two were classified by both classification systems as one syndrome, two were classified as one syndrome by the DSM-III-R but as two syndromes by the CBCL, and two were classified as two syndromes by the DSM-III-R but as one syndrome by the CBCL. The quality of the hypotheses was determined by means of four dependent variables selected from an overview of qualitative criteria: explanatory value, redundancy, possibility of operationalization, and specificity. No differences between the CBCL and the control groups were found. The DSM group performed better than the control group regarding explanatory value and redundancy. The DSM-III-R group also scored better than the CBCL group regarding explanatory value, particularly when the number of identified syndromes was two for the CBCL and one for the DSM-III-R.     

Two simple classes of mastery scores based on the beta-binomial model

Two simple classes of mastery scores which are suitable for hand calculations are presented for beta-binomial test score distributions combined with linear and cubic referral success. The models provide a simple way to explore the consequences of selecting an arbitrary mastery score. Such assessment would be useful whenever the test user is not willing to posta priori a loss ratio, but wishes to look at the various consequences before aiming at a particular score.     

Stopping rules for multi-category computerized classification testing

Computerized classification testing (CCT) aims to classify persons into one of two or more possible categories to make decisions such as mastery/non-mastery or meet most/meet all/exceed. A defining feature of CCT is its stopping criterion: the test terminates when there is enough confidence to make a decision. There is abundant research on CCT with a single cut-off, and two common stopping criteria are the sequential probability ratio test (SPRT) statistic and the generalized likelihood ratio statistic (GLR). However, there is a relative scarcity of research extending the SPRT to the multi-hypothesis case for when there is more than one cut-off. In this paper, we propose a new multi-category GLR (mGLR) statistic as well as a stochastically curtailed version of the CCT with three or more categories. A simulation study was conducted to show that the mGLR statistic outperformed the existing stopping rules by generating shorter average test length without sacrificing classification accuracy. Results also revealed that the stochastically curtailed mGLR successfully increased test efficiency in certain testing conditions.