Model-based measurement of latent risk in time series with applications

Summary.  Risk is at the centre of many policy decisions in companies, governments and other institutions. The risk of road fatalities concerns local governments in planning countermeasures, the risk and severity of counterparty default concerns bank risk managers daily and the risk of infection has actuarial and epidemiological consequences. However, risk cannot be observed directly and it usually varies over time. We introduce a general multivariate time series model for the analysis of risk based on latent processes for the exposure to an event, the risk of that event occurring and the severity of the event. Linear state space methods can be used for the statistical treatment of the model. The new framework is illustrated for time series of insurance claims, credit card purchases and road safety. It is shown that the general methodology can be effectively used in the assessment of risk.     

Issues in blinded sample size re-estimation

The utility of blinded sample size re-estimation for clinical trials depends on the ability to estimate variability without providing information about the true treatment difference, and on some reasonable assurance that the method is not likely to cause the sample size to be increased when the treatment effect is better than anticipated. We show that violations of these properties are unlikely to occur in practice.     

The Integration of Didactic and Experiential Learning in the Teaching of Group Work

This paper presents findings on the effects of sex on salary differentials between men and women faculty in schools of social work in the United States and Canada. Data analysis involved variables such as rank, doctorate, publications, experience, and ethnicity in order to isolate the effects of sex on salary. The results indicate that there is a significant difference in mean salaries of men and women when these five variables are controlled for, and even on all possible combinations of them. Thus conventional criteria to determine salary levels are applied selectively to men and women faculty.     

Social programs and household size: evidence from New York city

What determines how many adults live in a house? How do people divide themselves up among households? Average household sizes vary substantially, both over time and in the cross-section. In this paper, we describe how a variety of government policies affect living arrangements, intentionally or not. Using data from a survey of households in New York City, we find that these incentives appear to have an impact. Specifically, households receiving these housing and income subsidies are smaller on average (measured by number of adults). The impacts appear to be considerably larger than those that would occur if the programs were lump-sum transfers. Small average household size can be extremely expensive in terms of physical and environmental resources, higher rents, and possibly homelessness. Thus, we encourage policymakers to pay greater heed to the provisions built into various social policies that favor smaller households.     

An evaluation of repertory grid technique in social work education

Social work educators need to develop a repertoire of methods to help students and practitioners reflect on and learn from practice. A matched subjects experimental research design was used to evaluate the use of repertory grid technique with cohorts of students from two social work qualifying courses. Students found completing and discussing computer analyses of grids a useful adjunct to conventional supervision. Grid completion was also associated with improved course performance.