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.     

Exposure to community violence and social support as predictors of anxiety and social and emotional behavior among African American children

We examined the effects of exposure to violence and social support on self-reported state and trait anxiety and parental rated problem behaviors among school-aged African-American children in low and high violence areas. Ninety-seven (97) fourth through sixth graders and their parents were interviewed about exposure to community violence, social support, and state and trait anxiety. Results indicate that trait anxiety was correlated positively with exposure to violence and negatively with social support. State anxiety was correlated negatively with family social support. Problem behaviors were correlated negatively with family support and income. Hierarchial multiple regression analyses indicated that children's reports of their exposure to community violence continued to explain significant variability in trait anxiety, and problem behavior after controlling for both income and social support measures. Social support from peers, family and teachers played differential roles in predicting problem behaviors among children from high and lower violence areas. These findings suggest that in planning intervention programs for children exposed to violence, greater attention to empowering parents to support their children, to fostering peer group support, and to bolstering teacher support may be useful, but attention to the underlying socio-political causes of violence exposure is essential.     

Acceleration model in the heterogeneous case of the general graded response model

A new model, called acceleration model, is proposed in the framework of the heterogenous case of the graded response model, based on processing functions defined for a finite or enumerable number of steps. The model is expected to be useful in cognitive assessment, as well as in more traditional areas of application of latent trait models. Criteria for evaluating models are proposed, and soundness and robustness of the acceleration model are discussed. Graded response models based on individual choice behavior are also discussed, and criticisms on model selection in terms of fitnesses of models to the data are also given.This research was supported by the Office of Naval Research (N00014-90-J-1456).     

Models for measurement,precision, and the nondichotomization of graded responses

It is common in educational, psychological, and social measurement in general, to collect data in the form of graded responses and then to combine adjacent categories. It has been argued that because the division of the continuum into categories is arbitrary, any model used for analyzing graded responses should accommodate such action. Specifically, Jansen and Roskam (1986) enunciate ajoining assumption which specifies that if two categoriesj andk are combined to form categoryh, then the probability of a response inh should equal the sum of the probabilities of responses inj andk. As a result, they question the use of the Rasch model for graded responses which explicitly prohibits the combining of categories after the data are collected except in more or less degenerate cases. However, the Rasch model is derived from requirements of invariance of comparisons of entities with respect to different instruments, which might include different partitions of the continuum, and is consistent with fundamental measurement. Therefore, there is a strong case that the mathematical implication of the Rasch model should be studied further in order to understand how and why it conflicts with the joining assumption. This paper pursues the mathematics of the Rasch model and establishes, through a special case when the sizes of the categories are equal and when the model is expressed in the multiplicative metric, that its probability distribution reflects the precision with which the data are collected, and that if a pair of categories is collapsed after the data are collected, it no longer reflects the original precision. As a consequence, and not because of a qualitative change in the variable, the joining assumption is destroyed when categories are combined. Implications of the choice between a model which satisfies the joining assumption or one which reflects on the precision of the data collection considered are discussed.     

Computer games,self-esteem and gratification of needs in adolescents

Playing computer games has become an increasingly popular leisure time activity amongst adolescents, but concerns have been expressed over possible associated consequences. One research area has investigated reasons for playing, and two prior explanations relate it to the functional concepts of ‘electronic friendship’ and ‘self-esteem’. A questionnaire study was conducted among 120 adolescents to obtain information on a number of measures including gratification of needs and self-esteem. Results showed that playing computer games is equally popular with males and females, but males spend more time on it. Positive correlations between playing and items on the needs scales were obtained. In particular males who were heavy players scored highly on the ‘preference to friends’ need, but interestingly they were also likely to see their friends more often outside school, thus providing no support for the theory that computer games are taking the place of normal social interaction. For females there was evidence of a negative relationship between self-esteem and need gratification through playing computer games. However more adolescents spend much more time watching television than playing computer games. These results are discussed in the context of previous research.     

Resilience in siblings of children with sickle cell disease

This pilot study was conducted to identify factors responsible for promoting resilience in siblings of children with sickle cell disease. Twenty siblings (10–17 years of age) of children (5–13 years) with sickle cell disease were selected from the Pediatric Clinic of Howard University Center for Sickle Cell Disease. The siblings responded to questionnaires, and the data obtained was analyzed by chi-square for association. The results indicated that age, birth order, and gender had no effect on resilience in the siblings. However, family size, number of parents in the home, sibling's knowledge of the illness, degree of morbidity of the illness, socioeconomic status of the family, and parents' attitudes and childrearing practices were all found to affect resilience. These findings provide additional insight into the psychosocial aspects of, and genetic counseling for sickle cell disease, as well as for other chronic genetic disorders.     

Departure from normal assumptions: A promise for future psychometrics with substantive mathematical modeling

Normal assumptions have been used in many psychometric methods, to the extent that most researchers do not even question their adequacy. With the rapid advancement of computer technologies in recent years, psychometrics has extended its territory to include intensive cognitive diagnosis, etcetera, and substantive mathematical modeling ha become essential. As a natural consequence, it is time to consider departure from normal assumptions seriously. As examples of models which are not based on normality or its approximation, the logistic positive exponent family of models is discussed. These models include the item task complexity as the third parameter, which determines the single principle of ordering individuals on the ability scale.     

Unbiased estimators of ability parameters,of their variance,and of their parallel-forms reliability

Given known item parameters, unbiased estimators are derived i) for an examinee's ability parameter and for his proportion-correct true score, ii) for the variances of and across examinees in the group tested, and iii) for the parallel-forms reliability of the maximum likelihood estimator .This work was supported in part by contract N00014-80-C-0402, project designation NR 150-453 between the Office of Naval Research and Educational Testing Service. Reproduction in whole or in part is permitted for any purpose of the United States Government.     

Maximum likelihood estimation of item response parameters when some responses are omitted

A theoretical model is given for dealing with omitted responses. Two special cases are investigated.This work was supported in part by contract N00014-80-C-0402, project designation NR 150-453 between the Office of Naval Research and Educational Testing Service. Reproduction in whole or in part is permitted for any purpose of the United States Government.