A logistic regression model for characterizing differential item functioning (DIF) between two groups is presented. A distinction is drawn between uniform and nonuniform DIF in terms of the parameters of the model. A statistic for testing the hypothesis of no DIF is developed. Through simulation studies, it is shown that the logistic regression procedure is more powerful than the Mantel-Haenszel procedure for detecting nonuniform DIF and as powerful in detecting uniform DIF.

The Mantel-Haenszel (MH) procedure is sensitive to only one type of differential item functioning (DIF). It is not designed to detect DIF that has a nonuniform effect across trait levels. By generalizing the model underlying the MH procedure, a more general DIF detection procedure has been developed (Swaminathan & Rogers, 1990). This study compared the performance of this procedure—the logistic regression (LR) procedure—to that of the MH procedure in the detection of uniform and nonuniform DIF in a simulation study which examined the distributional properties of the LR and MH test statistics and the relative power of the two procedures. For both the LR and MH test statistics, the expected distributions were obtained under nearly all conditions. The LR test statistic did not have the expected distribution for very difficult and highly discriminating items. The LR procedure was found to be more powerful than the MH procedure for detecting nonuniform DIF and as powerful in detecting uniform DIF. Index terms: differential item functioning, logistic regression, Mantel-Haenszel statistic, nonuniform DIF, uniform DIF. The Mantel-Haenszel (MH) procedure is currently one of the most popular procedures for detecting differential item functioning (DIF). The primary reasons for its popularity include its computational simplicity, ease of implementation, and associated test of statistical significance. These advantages, however, are obtained at the cost of some generality. The MH procedure is designed to detect uniform DIF and may not be sensitive to nonuniform DIF. Uniform DIF exists if there is no interaction be

The measurement of marital adjustment remains of major concern to researchers and clinicians. In spite of criticism, several research studies have reported the use of various measures of marital adjustment, most recently the Spanier Dyadic Adjustment Scale (DAS). This paper reports the field-testing and preliminary validation of a series of items from the DAS which have been previously suggested to be nearly as accurate as the entire scale for classifying respondents' marital adjustment. Data from a total of 545 married, living together, separated, and divorced persons revealed that the abbreviated form of the DAS validly differentiated between persons who in their perception were happy in their relationship and those who were not. The usefulness of this abbreviated scale for researchers and clinicians is discussed.

Investigation of the factor structure of the Parenting Sense of Competence Scale (PSOC) was conducted with an Australian sample of 849 mothers and 329 fathers. Two factors of Satisfaction and Efficacy were found that were largely consistent with previous research. In addition, a third factor reflecting interest in the parenting role emerged. The Satisfaction factor was strongly correlated with measures of child behaviour, parent wellbeing, and parenting style. Efficacy and Interest showed few correlations with these variables. Parent and child gender were not related to factor scores and child age showed a small relationship with PSOC scores for very young children. Use of the revised scale with separate scoring keys for mothers and fathers is recommended.

Better methods of providing information for long-term survivors of stroke, and for addressing their emotional and psychological needs are required. Primary care could be a key setting for helping to provide more inclusive services for both patient and carer.