Parameter estimation in latent trait models

Latent trait models for binary responses to a set of test items are considered from the point of view of estimating latent trait parameters=( ₁, , _n ) and item parameters=( ₁, , _k ), where _j may be vector valued. With considered a random sample from a prior distribution with parameter, the estimation of (, ) is studied under the theory of the EM algorithm. An example and computational details are presented for the Rasch model.This work was supported by Contract No. N00014-81-K-0265, Modification No. P00002, from Personnel and Training Research Programs, Psychological Sciences Division, Office of Naval Research. The authors wish to thank an anonymous reviewer for several valuable suggestions.     

Sociolinguistic contexts of the preschool

Two studies were conducted to determined the effects of specific learning centers on preschoolers' functional uses of language. In Study 1, preschoolers in three separate same-age classrooms (2-, 3-, and 5-year-olds) were observed on a time sampling scheduling during their free play periods for four weeks. Preschoolers' individual utterances were coded as serving one or more than one function; functions were defined following Halliday. The housekeeping and block centers tended to elicit the most individual and multifunctional utterances. The fantasy play and social interaction among children in these centers were thought to be responsible for this mature use of language.In Study 2, same-age and same-sex dyads from two age groups (4- and 5-year-olds) were observed in experimental settings playing with blocks alone and with dramatic props alone. Both contexts elicited a predominance of imaginative language, though the dramatic context elicited more imaginative language than the blocks. With age, children generated more individual functions and multifunctional utterances.     

Choice, changeover, and travel: A quantitative model

Six pigeons were trained on concurrent variable-interval schedules in which responding on fixed-interval schedules was required to give access to the alternate schedule. Responding on the concurrent schedules was not allowed, after changing over had commenced, until the changeover schedule had been completed. In Parts 1 to 3 of the experiment, the changeover fixed-interval schedules were equal and were 0 s, 10 s, and 20 s, respectively. In each part, the relative frequency of reinforcement obtained on the concurrent schedules was varied over at least five conditions. In Part 4, the concurrent schedules were equal, and one changeover fixed-interval schedule was twice the other. Under these conditions, the absolute sizes of the changeover schedules were varied. Increasing the changeover requirement from 0 s to 10 s (Parts 1 and 2) resulted in increases in the sensitivity of behavior allocation to reinforcers obtained, but no further increase was obtained when the changeover schedules were increased to 20 s (Part 3). In Part 4, performance was biased towards the concurrent schedule that took less time to enter. These results are consistent with a subtractive punishment model of travel in which the degree of punishment is measured by the number of reinforcers apparently lost from a schedule when the subject changes to that schedule. Absolute times spent on the main keys could be accurately described by a previous model of changeover performance.     

Axiomatic and numerical conjoint measurement: An evaluation of diagnostic efficacy

Synthetic data are used to examine how well axiomatic and numerical conjoint measurement methods, individually and comparatively, recover simple polynomial generators in three dimensions. The study illustrates extensions of numerical conjoint measurement (NCM) to identify and model distributive and dual-distributive, in addition to the usual additive, data structures. It was found that while minimum STRESS was the criterion of fit, another statistic, predictive capability, provided a better diagnosis of the known generating model. That NCM methods were able to better identify generating models conflicts with Krantz and Tversky's assertion that, in general, the direct axiom tests provide a more powerful diagnostic test between alternative composition rules than does evaluation of numerical correspondence. For all methods, dual-distributive models are most difficult to recover, while consistent with past studies, the additive model is the most robust of the fitted models.Douglas Emery is now at the Krannert Graduate School of Management, Purdue University, West Lafayette, IN, on leave from the University of Calgary.     

New assessment systems for residential treatment,management, research,and evaluation: A symposium

An introduction and overview are presented to new observational assessment systems for ongoing assessment and monitoring of both staff and resident (client or patient) functioning in residential treatment programs for emotionally disturbed and mentally retarded adults.Preparation of articles and the research and development on which the articles are based was supported, in part, by Public Health Service Grants MH-15553 and MH-25464 from the National Institute of Mental Health, and by grants from the Joyce Foundation and the Illinois Department of Mental Health and Developmental Disabilities.A symposium presented at the 87th Annual Meetings of the American Psychological Association, New York City, September 1979.     

Systems use to objectify program evaluation,clinical, and management decisions

The utility of the observational assessment systems at different levels — from local clinical to systemwide management — is outlined. An overview is provided of TSBC information applied to individualized problem identification and programming/monitoring, discharge and competency determinations, and both absolute and comparative program evaluation. The utility of SRIC information for prgoramming/monitoring and for staff training and evaluation is outlined in addition to the applied uses of the information of the assessment systems in combination. Once implemented, the continuous data from the systems allow for empirically based self-corrective improvements in the quality of mental health services while automatically providing a basis for legal documentation and accurate cost/effectiveness comparisons of mental health programs.Preparation of this article and the research and development on which the article is based were supported, in part, by Public Health Service Grants MH-15553 and MH-25464 from the National Institute of Mental Health, and by grants from The Joyce Foundation and the Illinois Department of Mental Health and Developmental Disabilities.Presented at the 87th Annual Meetings of the American Psychological Association, New York City, September 1979, as part of a symposium on New assessment systems for residential treatment, management, research, and evaluation.     

Relationship between career maturity and self-concepts of suburban and urban middle- and urban lower-class preadolescent black males

The relationship between career maturity and self-concepts of 252 sixth-grade black males was investigated. Student samples of suburban and urban middle- and urban lower-class were drawn from 42 different school settings located in Monroe, Erie, and Westchester Counties of New York State. The Attitude Scale of the Career Maturity Inventory and the Coopersmith Self-Esteem Inventory were used to assess the association of career maturity and self-concepts. Results indicated relatively weak-positive relationships between career maturity and self-concepts. Significant career maturity differences were found. However, self-concepts of the three groups were not statistically significantly different. Of the set of independent variables predicting and estimating variance accounted for (socioeconomic status, family intactness, place of residence, and reading), socioeconomic status was found to have the strongest predictive value on career maturity. It was suggested that researchers examine elementary school black students' career development in view of the group with whom they identify most.     

Peripheral information extraction: A developmental examination of reading processes

Three experiments examining the information extraction processes are presented. In Experiments I and II, adults and children were presented paragraphs to read and search for specified targets, respectively. Two types of typographical (spatial) manipulations were used: case of the letters within the paragraphs was as normally experienced, or in alternating upper and lower case letters. Spacing between words was either as normal, filled with a neutral symbol, or absent. The response measures were reading and search speed in words per minute. Sensitivity to case (word shape) and space (word boundary) increased as a function of experience and was different for reading compared with search. In Experiment III subjects were asked to judge whether briefly presented pairs of letters were the same or different. Retinal (spatial) location was varied from trial to trial; dependent measure was reaction time. Results showed a developmental progression in response time with complex interactions. Theoretical interpretations of these data are discussed in support of the initial stage of Hochberg's peripheral to cognitive search guidance model.     

Verbal rehearsal and selective attention in children with learning disabilities: A developmental lag

To investigate the development of verbal rehearsal strategies and selective attention in learning disabled children, Hagen's Central-Incidental task was administered to younger learning disabled (M CA = 8.68 years) and normal (M CA = 8.62 years) boys in Experiment 1 and to intermediate (M CA = 10.18 years) and older (M CA = 13.48 years) learning disabled boys in Experiment 2. Also, in Experiment 2, an experimentally induced verbal rehearsal condition was included to determine its effects on serial recall and selective attention performance. In Experiment 1, the serial postion curve of the normals revealed both a primacy and a recency effect, whereas that of the learning disabled revealed a recency effect only. In Experiment 2, both the intermediate and the older learning disabled exhibited both primacy and recency effects under both standard and rehearsal conditions. A developmental analysis of central recall for the three learning disabled groups revealed constant age-related increases in overall central recall and in primacy recall. That the normals recalled more central, but not more incidental, information than the learning disabled in Experiment 1 suggests that the learning disabled are deficient in selective attention. Correlational findings suggest that the selective attention of the learning disabled improves with age. The results were interpreted as support for the hypothesis of a developmental lag in the learning disabled population.