A multilevel analysis of longitudinal ordinal data: evaluation of the level of physical performance of women receiving adjuvant therapy for breast cancer

Longitudinal health-related quality-of-life (QOL) data are often collected as part of clinical studies. Here two analyses of QOL data from a prospective study of breast cancer patients evaluate how physical performance is related to factors such as age, menopausal status and type of adjuvant treatment. The first analysis uses summary statistic methods. The same questions are then addressed using a multilevel model. Because of the structure of the physical performance response, regression models for the analysis of ordinal data are used. The analyses of base-line and follow-up QOL data at four time points over two years from 257 women show that reported base-line physical performance was consistently associated with later performance and that women who had received chemotherapy in the month before the QOL assessment had a greater physical performance burden. There is a slight power gain of the multilevel model over the summary statistic analysis. The multilevel model also allows relationships with time-dependent covariates to be included, highlighting treatment-related factors affecting physical performance that could not be considered within the summary statistic analysis. Checking of the multilevel model assumptions is exemplified.     

Middle East and North African Information Resources: Western Libraries Navigating the Montage

The spotlight for this edition of “The Balance Point” is on publishing and collection development issues in the Middle East and North African (MENA) region of the world. While reflecting upon recent events in the Middle East and Europe, the column editor began to wonder what impact current issues have on publishing, collection development, scholarly communication, and discoverability of resources from the MENA region, as well as the impact these issues have on the collection development activities of Western academic research libraries. Blair Kuntz, the Near and Middle Eastern studies librarian at the University of Toronto Library, was asked to coauthor the column and to share his insights regarding the region with readers. The authors discuss the myriad issues and the mosaic of collection development issues for the MENA region.     

Uniformly best estimation in linear regression when prior information is fuzzy

Modeling prior information as a fuzzy set and using Zadeh’s extension principle, a general approach is presented how to rate linear affine estimators in linear regression. This general approach is applied to fuzzy prior information sets given by ellipsoidal α-cuts. Here, in an important and meaningful subclass, a uniformly best linear affine estimator can be determined explicitly. Surprisingly, such a uniformly best linear affine estimator is optimal with respect to a corresponding relative squared error approach. Two illustrative special cases are discussed, where a generalized least squares estimator on the one hand and a general ridge or Kuks–Olman estimator on the other hand turn out to be uniformly best.     

Information,reflection, and successful job search: A labor market policy experiment

Jobseekers, especially young people with little experience on the job market, face several challenges. They need to know which jobs are suited for them, where to find them, how to apply, and they need resilience in the face of repeated rejections. Previous research has shown that receiving information and reflecting on how to search for a job enhance self-efficacy and search motivation, thereby reducing the duration of unemployment spells. Following up on these results, we conducted an experiment in cooperation with the Austrian Ministry of Social Affairs which combines an “information nudge” in the form of a short video-clip with what we call “reflection nudge” in the form of an online survey. We find that a treatment combining reflection and information reduces job search duration of young unemployed people with a low level of formal education. Considering the low costs of the intervention, efficiency is very high.