Shrinkage estimation of linear combinations of true scores

This paper is concerned with combining observed scores from sections of tests. It is demonstrated that in the presence of population information a linear combination of true scores can be estimated more efficiently than by the same linear combination of the observed scores. Three criteria for optimality are discussed, but they yield the same solution which can be described and motivated as a multivariate shrinkage estimator.Input from Eric Bradlow, Charles Lewis, and Linda Zeger is acknowledged. Research for this paper was funded by the Program Research Council (ETS). Suggestions of the Editor and of anonymous referees were instrumental in several improvements of the paper.     

A measure of parental stress in mothers with small children: dimensionality, stability and validity

Self-reported parental stress was investigated in three samples of mothers with small children, using a Swedish version of the Parenting Stress Index (PSI). Dimensionality in experienced stress using items from six PSI Parent Domain subscales and eight new items was examined in factor analyses of data from a nationwide representative sample. Cross-validation proved the chosen factor pattern to be stable. Based on an oblique 5-factor solution new subscales were constructed. A second order factor analysis indicated influence from a higher order factor, seen as a general parental stress construct. High alpha coefficients revealed that homogeneous subscales had been formed. Test-retest correlations indicated good stability over a mean time period of 30 days. Influences from maternal background variables were found, but no relation to child age or gender. Global estimates of parental stress, reported child problems, mothers' scoring on the Edinburgh Postnatal Depression Scale and two measures of social support all correlated significantly with overall parental stress, and with some subscales. The justification of the subscale approach to parental stress was discussed. It was concluded that the PSI in its present form could be used as a reliable and valid instrument for measuring experienced parental stress in mothers of young children.     

Residualanalysis in the polytomous rasch model

Residuals for check of model fit in the polytomous Rasch model are examined. Comparisons are made between using counts for all response pattern and using item totals for score groups for the construction of the residuals. Comparisons are also, for the residuals based on score group totals, made between using as basis the item totals, or using the estimated item parameters. The developed methods are illustrated by two examples, one from a psychiatric rating scale, one from a Danish Welfare Study.     

Some neglected problems in IRT

The paper addresses three neglected questions from IRT. In section 1, the properties of the “measurement” of ability or trait parameters and item difficulty parameters in the Rasch model are discussed. It is shown that the solution to this problem is rather complex and depends both on general assumptions about properties of the item response functions and on assumptions about the available item universe. Section 2 deals with the measurement of individual change or “modifiability” based on a Rasch test. A conditional likelihood approach is presented that yields (a) an ML estimator of modifiability for given item parameters, (b) allows one to test hypotheses about change by means of a Clopper-Pearson confidence interval for the modifiability parameter, or (c) to estimate modifiability jointly with the item parameters. Uniqueness results for all three methods are also presented. In section 3, the Mantel-Haenszel method for detecting DIF is discussed under a novel perspective: What is the most general framework within which the Mantel-Haenszel method correctly detects DIF of a studied item? The answer is that this is a 2PL model where, however, all discrimination parameters are known and the studied item has the same discrimination in both populations. Since these requirements would hardly be satisfied in practical applications, the case of constant discrimination parameters, that is, the Rasch model, is the only realistic framework. A simple Pearsonx ² test for DIF of one studied item is proposed as an alternative to the Mantel-Haenszel test; moreover, this test is generalized to the case of two items simultaneously studied for DIF.     

Parallel short forms of the family of origin scale: Evidence of their reliability and validity

Two parallel short forms of the Family of Origin Scale were developed from data provided by 69 women and 63 men who completed the full Family of Origin Scale along with a variety of measures of family-of-origin characteristics. Data on the reliability and validity of the short forms are provided and discussed. The results indicate that both short forms are strongly and significantly correlated with each other and with the full-scale version of the FOS and that they share its reliability and validity characteristics to a very high degree.     

An extension of the partial credit model with an application to the measurement of change

The partial credit model is considered under the assumption of a certain linear decomposition of the item × category parameters _ih into basic parameters _j. This model is referred to as the linear partial credit model. A conditional maximum likelihood algorithm for estimation of the j is presented, based on (a) recurrences for the combinatorial functions involved, and (b) using a quasi-Newton approach, the so-called Broyden-Fletcher-Goldfarb-Shanno (BFGS) method; (a) guarantees numerically stable results, (b) avoids the direct computation of the Hesse matrix, yet produces a sequence of certain positive definite matricesB _k ,k=1, 2, ..., converging to the asymptotic variance-covariance matrix of the . The practicality of these numerical methods is demonstrated both by means of simulations and of an empirical application to the measurement of treatment effects in patients with psychosomatic disorders.The authors thank one anonymous reviewer for his constructive comments. Moreover, they thankfully acknowledge financial support by the Österreichische Nationalbank (Austrian National Bank) under Grant No. 3720.     

A spanish translation and validation of the daily stress inventory and a comparison of the level of stress experienced by three culturally distinct hispanic groups

Two studies were conducted, the first to establish a valid Spanish version of the Daily Stress Inventory (DSI). A second study was conducted using the bilingual version of the DSI to assess differences in the level of stress experienced by three selected Hispanic groups: (a) very Hispanic/Hispanic-oriented bicultural, (b) true bicultural, and (c) Anglo-oriented bicultural/very Anglicized as determined by the adapted version of the Acculturation Rating Scale for Mexican Americans (ARSMA). It was expected that stress levels would be highest for the least acculturated group. The results of the first study indicate that the Bilingual DSI scores are highly correlated with the scores of the original DSI when both instruments are responded to simultaneously by fully bilingual individuals. In Study 2, the initial data analyses showed no difference in the level of stress reported by Hispanics at different levels of acculturation as measured by the ARSMA. When a median-split method was employed, differences in the DSI I/E measures between the two groups were significant, suggesting that acculturation level may be related to stress level.     

Dimensionality and validity of two scales measuring different aspects of self-esteem

Two self-esteem (SE) scales aimed to measure self-esteem–conceptualized primarily (a) as the individual's ego-integrated libidinous and aggressive drives and their derivatives (Basic SE), and (b) as the need to earn self-esteem by competence and others' appraisal (Earning SE)–were developed and factor analysed. In order to construct- and cross-validate the scales, they were related to other well-known personality scales as well as to a projective technique (TAT) in two independent samples of first semester psychology students ( n = 153, n = 82). The empirical factor structure coincided well with the theoretical formulations. Basic SE showed concurrent validity being highly correlated ( p < 0.001) with both Rosenberg's and Coopersmith's self-esteem scales and highly or moderately with Neuroticism, Extraversion (EPQ) and Test-Anxicty (TAS) in both samples. Earning SE gained some construct validation by its relation to Type-A scores (JAS) as well as to verbal fantasy stories on TAT-pictures measuring Need of Achievement.     

Childhood stress: Perceptions of children and professionals

An assessment instrument was developed to measure children's perceptions of stressors in their lives, as well as their experiences and emotional reactions to these stressors. Two approaches from the adult literature, major life events and daily hassles, were compared for children. In addition, a comparison between children's and professionals' ratings of the severity of various stressors was made, as well as an examination of the relationship of experience and self-reported reaction to children's ratings. Results indicate that children's ratings of the severity of stressors do differ from adults', particularly when children have experienced the stressor. Further investigation in the study of childhood stress incorporating children's perceptions is proposed.