Risk of Error and the Kappa Coefficient of a Binary Diagnostic Test in the Presence of Partial Verification

The accuracy of a binary diagnostic test is usually measured in terms of its sensitivity and its specificity, or through positive and negative predictive values. Another way to describe the validity of a binary diagnostic test is the risk of error and the kappa coefficient of the risk of error. The risk of error is the average loss that is caused when incorrectly classifying a non-diseased or a diseased patient, and the kappa coefficient of the risk of error is a measure of the agreement between the diagnostic test and the gold standard. In the presence of partial verification of the disease, the disease status of some patients is unknown, and therefore the evaluation of a diagnostic test cannot be carried out through the traditional method. In this paper, we have deduced the maximum likelihood estimators and variances of the risk of error and of the kappa coefficient of the risk of error in the presence of partial verification of the disease. Simulation experiments have been carried out to study the effect of the verification probabilities on the coverage of the confidence interval of the kappa coefficient.     

Educational responses to immigrant students in Madrid

During the last few years, changes in the Spanish educational system have had a far reaching impact. Several factors have been critical: (1) the progressive decentralization of education by the government, now a responsibility of regional governments; (2) the extension of compulsory education to the age of 16; and finally (3) the increase in the number of immigrant students, which has significantly added to the existing cultural diversity. The enrolment of immigrant students in Spanish schools is a relatively recent phenomenon (starting 15 years ago) when compared with other European countries. Madrid is the region in Spain with the largest number of students. As most of these students were born outside of Spain, we cannot yet speak of a second generation. The research described here investigated how the educational system in Madrid confronted the challenge of an increasing number of immigrant students. The institutional response was the Madrid Regional Government’s Compensatory Education Regional Plan. This encompasses several measures, which are described here. After a critical analysis of educational policies pertaining to immigrant pupils, the paper suggests ways of overcoming a purely compensatory approach. Intercultural education plays a key role is such considerations.     

The Changing Practices and Meanings of Grandparenthood. Reflections on the Demographical Trends and Changing Representations of Ageing

Deep demographical shifts in western societies are significantly influencing the patterns of family life including the various forms of solidarity between generations. At the same time, we are facing significant changes in the social representation of ageing, which also influence the ways in which the roles of seniors in society are perceived and how the meaning of old age is constructed. The paper highlights the significance of these changes for the possible (re)definition of grandparenthood. It discusses the ways in which these demographical changes, the current heterogeneity of family life, and changing representations of ageing can affect the practices and meanings of grandparenthood. Simultaneously, it points out the need to analyse grandparenthood as a role which is strongly gendered.     

The Role of Religiousness and Gender in Sexuality Among Mexican Adolescents

This study examined the role of religiousness and gender in age at first intercourse, and sexual expectations and values in Mexico, a macrocontext where the majority is Mexican and Catholic (83%). Participants were Catholic and nonreligious adolescents (54% girls) attending middle (71%) or high school. Findings indicated that Catholic adolescents engaged in sexual intercourse at later ages than nonreligious adolescents. Both religious attendance and importance of religion and values in sexual decision making were associated with more conservative sexual values. Boys who were raised Catholic were more likely to endorse female virginity values and were less likely to expect to wait to have sex until married than nonreligious boys. These associations were not significant among girls. Catholic boys may be more likely to internalize sexual double standard beliefs regarding premarital sex than nonreligious boys. This study expands our understanding of the role of religiousness in Mexican adolescents’ sexuality.     

Time to Diagnosis: Accounting for Differential Endpoint Follow-up in Multi-Cohort Studies

Cox regression is widely used to analyze discrete survival time data. Differential endpoint follow-up across sub-cohorts where distribution of a covariate varies may cause typical estimators to be biased or inefficient. We demonstrate that with Cardiovascular Health Study data for incident type 2 diabetes. Two cohorts with extremely different race distribution have differential follow-up for fasting glucose levels. We study various scenarios of Cox regression. We suggest an alternative approach, Poisson generalized estimating equations with an offset to accommodate the differential follow-up. We use simulations to contrast the methods.