Testing for DIF in a model with single peaked item characteristic curves: The parella model

The PARELLA model is a probabilistic parallelogram model that can be used for the measurement of latent attitudes or latent preferences. The data analyzed are the dichotomous responses of persons to items, with a one (zero) indicating agreement (disagreement) with the content of the item. The model provides a unidimensional representation of persons and items. The response probabilities are a function of the distance between person and item: the smaller the distance, the larger the probability that a person will agree with the content of the item. This paper discusses how the approach to differential item functioning presented by Thissen, Steinberg, and Wainer can be implemented for the PARELLA model. Requests for the PARELLA software should be sent to Iec Progamma PO Box 841, 9700 AV Groningen, The Netherlands.     

Polytomous IRT models and monotone likelihood ratio of the total score

In a broad class of item response theory (IRT) models for dichotomous items the unweighted total score has monotone likelihood ratio (MLR) in the latent trait. In this study, it is shown that for polytomous items MLR holds for the partial credit model and a trivial generalization of this model. MLR does not necessarily hold if the slopes of the item step response functions vary over items, item steps, or both. MLR holds neither for Samejima's graded response model, nor for nonparametric versions of these three polytomous models. These results are surprising in the context of Grayson's and Huynh's results on MLR for nonparametric dichotomous IRT models, and suggest that establishing stochastic ordering properties for nonparametric polytomous IRT models will be much harder.Hemker's research was supported by the Netherlands Research Council, Grant 575-67-034. Junker's research was supported in part by the National Institutes of Health, Grant CA54852, and by the National Science Foundation, Grant DMS-94.04438.     

Some improved diagnostics for failure of the Rasch model

Although several goodness of fit tests have been developed for the Rasch model for dichotomous items, most of them are of a global, asymptotic, and confirmatory type. This paper, based on ideas from a recent thesis by Van den Wollenberg, offers some suggestions for local, small sample, and exploratory techniques: difficulty plots for person groups scoring right and wrong on a specific item, a slope test per item based on a binomial distribution per score group, and a unidimensionality check based on an extended hypergeometric distribution per score group. This paper owes much to the inspiring and pioneering work of Arnold Van den Wollenberg, of which only minor aspects are criticized. Thanks go to Charles Lewis for stimulating discussions and for solutions to some programming problems.     

Response Mixture Modeling: Accounting for Heterogeneity in Item Characteristics across Response Times

In item response theory modeling of responses and response times, it is commonly assumed that the item responses have the same characteristics across the response times. However, heterogeneity might arise in the data if subjects resort to different response processes when solving the test items. These differences may be within-subject effects, that is, a subject might use a certain process on some of the items and a different process with different item characteristics on the other items. If the probability of using one process over the other process depends on the subject’s response time, within-subject heterogeneity of the item characteristics across the response times arises. In this paper, the method of response mixture modeling is presented to account for such heterogeneity. Contrary to traditional mixture modeling where the full response vectors are classified, response mixture modeling involves classification of the individual elements in the response vector. In a simulation study, the response mixture model is shown to be viable in terms of parameter recovery. In addition, the response mixture model is applied to a real dataset to illustrate its use in investigating within-subject heterogeneity in the item characteristics across response times.     

Interference in memory by process or content? A reply to Neath (2000)

The approach to the irrelevant sound effect by Neath (2000) is discussed in terms of the contrast between content-based and process-based interference. Four themes are highlighted: First, problematic features of the feature model are highlighted; second, results not considered by Neath are presented; third, empirical underpinnings of the feature model not related to the irrelevant-sound effect are questioned; last, the parsimony of the feature model is questioned. The balance of the evidence seems to be in favor of a process-based approach, on the grounds that it provides a comprehensive account of acoustic and taskbased factors within the irrelevant sound effect, for both speech and nonspeech sound.     

The impact of order incongruence between a task-irrelevant auditory sequence and a task-relevant visual sequence

A novel effect is reported in which serial recall of visual digits was disrupted to a greater degree by the presence of the same set of digits presented as an irrelevant auditory sequence than by the presence of irrelevant auditory consonants, but only when the order of the irrelevant digits was incongruent with that of the to-be-remembered digits (Experiment 1). Experiment 2 replicated this order-incongruence effect and showed also that disruption was dictated by the number of order-incongruent transitions but not by the number of novel tokens contained within the irrelevant sequence. The results favor an interference-by- process approach to the disruption of serial memory by irrelevant sound over approaches based on notions of interference by content and/or interference by depletion of attentional resources.     

Temporal aspects of passive movement-related corticomotor inhibition

We have previously shown that during rhythmic passive movement of the index finger, the amplitude of the motor evoke potential (MEP) of the first dorsal interosseous muscle (FDI) as the index finger moved through mid-range adduction, is significantly reduced compared to rest [Edwards, D. J., Thickbroom, G. W., Byrnes, M. L., Ghosh, S., & Mastaglia, F. L. (2002). Reduced corticomotor excitability with passive movement: A study using Transcranial Magnetic Stimulation. Human Movement Science 21, 533-540]. In the present study we have investigated the time-course of this phenomenon. We found that MEP amplitude was significantly reduced at the mid-range position in the first cycle of movement (50+/-6% of resting baseline values), and did not vary across subsequent cycles (10 cycles in 50 s), but that MEP amplitude returned to baseline values within 1s of cessation of movement. The results suggest that the pattern of afferent discharge set up by the kinematics of the movement acting at spinal or supraspinal levels underlies the inhibition observed, rather than an effect of central origin or a cumulative effect of ongoing cyclic movement.     

Temporal grouping in auditory spatial serial memory

Grouping effects in serial recall have been widely studied with verbal stimuli, but hardly ever with spatial stimuli and not at all with auditory spatial stimuli. In Experiment 1, we examined the influence of combined temporal and pitch grouping on recall of the locations from which bursts of white noise were presented. Similar to findings in verbal studies, effects of the grouping manipulation were found in performance accuracy, in the nature of order errors, and in the timing of responses. Experiment 2 was designed to distinguish the role played by pitch grouping from that played by temporal grouping, through independent manipulation of the presence of a shift in pitch and that of a temporal gap. The results showed that the temporal grouping manipulation determined performance and the pitch grouping manipulation did not. Similarities between our findings and those of verbal studies, and implications for the understanding of serial memory are discussed.     

Data, model, conclusion, doing it again

This paper explores the robustness of conclusions from a statistical model against variations in model choice (rather than variations in random sampling and random assignment to treatments, which are the usual variations covered by inferential statistics). After the problem formulation in section 1, section 2 presents an example from Box and Tiao in which variation in parent distribution is modeled for a one sample location problem. An adaptive Bayesian procedure permits to use a weighted mixture of parent distributions rather than choosing just one, such as a normal or a uniform distribution.In section 3 similar considerations are applied to an event history model for the influence of education and gender on age at first marriage, but here the conclusions are hardly influenced by the choice of the duration distribution. In section 4 a brief discussion of model choice in factor analysis and structural equation models is followed by a more elaborate treatment of the choice of integer valued slopes for item response functions in the OPLM model which is an extension of the Rasch model. A modest simulation study suggests that Adaptive Bayesian Modeling with a mixture of sets of slopes works better than fixing one set of postulated slopes.The paper concludes with some remarks on the roles and sources of prior distributions followed by a short epilogue which argues that simultaneous consideration of a class of models for the same data is sometimes superior to exclusively analyzing the data under one specific model chosen from such a class.This article is based on the Presidential Address Ivo W. Molenaar gave on June 20, 1998 at the 1998 Annual Meeting of the Psychometric Society held at the University of Illinois in Champaign, Illinois. Thanks is given to John Wiley & Sons and George C. Tiao for granting permission to reprint three figures from the book George C. Tiao wrote with George E. P. Box titled Bayesian Inference in Statistical Analysis.—EditorThanks are due to Anne Boomsma, Jeffrey Hoogland, Mark Huisman, Tom Snijders, Marijtje Van Duijn, and Norman Verhelst for suggesting improvements and/or assisting with data analyses.     

Refining Value Sensitive Design: A (Capability-Based) Procedural Ethics Approach to Technological Design for Well-Being

Science and Engineering Ethics - Fundamental questions in value sensitive design include whether and how high-tech products/artefacts could embody values and ethical ideals, and how plural and...