235 research outputs found
Monomial Crystals and Partition Crystals
No full textRecently Fayers introduced a large family of combinatorial realizations of the fundamental crystal B(Λ_0) for ^sl_n, where the vertices are indexed by certain partitions. He showed that special cases of this construction agree with the Misra-Miwa realization and with Berg's ladder crystal. Here we show that another special case is naturally isomorphic to a realization using Nakajima's monomial crystal
Implicit self-comparisons against others could bias quality of life assessments
No full textObjectives: To explore how patient-reported health related quality of life (HRQL) and global health status are affected by use of differing personal reference frames. We hypothesised that implicit comparisons against self at an earlier time, against healthy peers or against ill patients would greatly affect patients’ response values. Study design and setting: Patients in a randomised trial for treatment of Paget’s disease completed annual HRQL questionnaires. Supplementary questions were appended, asking the patients whether they were aware of having made implicit comparisons. Results: The majority of patients reported considering themselves a year ago (31% at baseline), themselves before becoming ill (23%) or other healthy people (24%), with similar proportions during follow up. Mean HRQL scores varied substantially according to the declared frame of reference, with differences as big as 19% of the scale score, or a standardised mean effect size of 0.74 standard deviations. Conclusion: Reported reference frames were associated with effects of similar magnitude to the differences in HRQL that are regarded as clinically important. This may be of particular concern in trials that andomise patients to management in different settings, such as treatment at home / in hospital, or surgery / chemotherapy, and might bias or obscure HRQL differences
Review : "Quality of life: the assessment, analysis and interpretation of patient-reported outcomes (2nd Ed.)" by Peter M. Fayers & David Machin
No full textAn updated version, this excellent text is a timely addition to the library of any nurse researching in oncology or other settings where individuals’ quality of life must be understood. Health-related quality of life should be a central aspect of studies concerned with health and illness. Indeed, considerable evidence has recently emerged in oncology and other research settings that selfreported quality of life is of great prognostic significance and may be the most reliable predictor of subsequent morbidity and mortality. From a nursing perspective, it is also gratifying to note that novel therapy and other oncology studies increasingly recognize the importance of understanding patients’ subjective experiences of an intervention over time and to ascertain whether patients perceive that a new intervention makes a difference to their quality of life and treatment outcomes. Measurements of quality of life are now routine in clinical trials of chemotherapy drugs and are often considered the prime outcome of interest in the cost/benefit analyses of these treatments. The authors have extensive experience in qualityof- life assessment in cancer clinical trials, where most of the pioneering work into quality of life has been conducted. That said, many of the health-related qualityof- life issues discussed are common to many illnesses, and researchers outside of cancer should find the book equally helpful
Deriving a preference-based utility measure for cancer patients from the European Organisation for the Research and Treatment of Cancer's Quality of Life Questionnaire C30: a confirmatory versus exploratory approach
No full textDaniel SJ Costa,1 Neil K Aaronson,2 Peter M Fayers,3,4 Peter S Grimison,5,6 Monika Janda,7 Julie F Pallant,8 Donna Rowen,9 Galina Velikova,10 Rosalie Viney,11 Tracey A Young,9 Madeleine T King1On behalf of the MAUCa Consortium1Psycho-oncology Co-operative Research Group, University of Sydney, Sydney, NSW, Australia; 2Division of Psychosocial Research and Epidemiology, The Netherlands Cancer Institute, Amsterdam, the Netherlands; 3Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, UK; 4Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; 5Chris O'Brien Lifehouse, 6Sydney Medical School, University of Sydney, Sydney, NSW, 7School of Public Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 8Rural Health Academic Centre, University of Melbourne, Shepparton, VIC, Australia; 9School of Health and Related Research, University of Sheffield, Sheffield; 10University of Leeds, St James's Institute of Oncology, Leeds, UK; 11Centre for Health Economics Research and Evaluation, University of Technology, Sydney, NSW, AustraliaBackground: Multi attribute utility instruments (MAUIs) are preference-based measures that comprise a health state classification system (HSCS) and a scoring algorithm that assigns a utility value to each health state in the HSCS. When developing a MAUI from a health-related quality of life (HRQOL) questionnaire, first a HSCS must be derived. This typically involves selecting a subset of domains and items because HRQOL questionnaires typically have too many items to be amendable to the valuation task required to develop the scoring algorithm for a MAUI. Currently, exploratory factor analysis (EFA) followed by Rasch analysis is recommended for deriving a MAUI from a HRQOL measure.Aim: To determine whether confirmatory factor analysis (CFA) is more appropriate and efficient than EFA to derive a HSCS from the European Organisation for the Research and Treatment of Cancer's core HRQOL questionnaire, Quality of Life Questionnaire (QLQ-C30), given its well-established domain structure.Methods: QLQ-C30 (Version 3) data were collected from 356 patients receiving palliative radiotherapy for recurrent/metastatic cancer (various primary sites). The dimensional structure of the QLQ-C30 was tested with EFA and CFA, the latter informed by the established QLQ-C30 structure and views of both patients and clinicians on which are the most relevant items. Dimensions determined by EFA or CFA were then subjected to Rasch analysis.Results: CFA results generally supported the proposed QLQ-C30 structure (comparative fit index =0.99, Tucker–Lewis index =0.99, root mean square error of approximation =0.04). EFA revealed fewer factors and some items cross-loaded on multiple factors. Further assessment of dimensionality with Rasch analysis allowed better alignment of the EFA dimensions with those detected by CFA.Conclusion: CFA was more appropriate and efficient than EFA in producing clinically interpretable results for the HSCS for a proposed new cancer-specific MAUI. Our findings suggest that CFA should be recommended generally when deriving a preference-based measure from a HRQOL measure that has an established domain structure.Keywords: multi attribute utility instrument, health state classification system, confirmatory factor analysis, exploratory factor analysis, European Organisation for the Research and Treatment of Cancer QLQ-C3
Health Measurement Scales: A Practical Guide to their Development and Use. By David L. Streiner and Geoffrey Norman. Oxford: Oxford University Press. 1989. 182 pp. £25.00
No full text
Practical handbook of sample size guidelines for clinical trials. Jonathon J. Shuster, CRC press inc., Boca Raton, Florida, 1993. no. of pages: 212, plus program on diskettes for IBM-PC (MSDOS) or Macintosh. price: £51. ISBN: 0-8493- 4487-5
No full textGeneral runner removal and the Mullineux map
No full textAbstractWe prove a new ‘runner removal theorem’ for q-decomposition numbers of the level 1 Fock space of type Ae−1(1), generalising earlier theorems of James–Mathas and the author. By combining this with another theorem relating to the Mullineux map, we show that the problem of finding all q-decomposition numbers indexed by partitions of a given weight is a finite computation
Translation procedures for standardised quality of life questionnaires: The European Organisation for Research and Treatment of Cancer (EORTC) approach
No full textBackground: The European Organisation for Research and Treatment of Cancer quality of life (EORTC QL) questionnaires are used in international trials and therefore standardised translation procedures are required. This report summarises the EORTC translation procedure, recent accomplishments and challenges. Methods: Translations follow a forward-backward procedure, independently carried out by two native-speakers of the target language. Discrepancies are arbitrated by a third consultant, and solutions are reached by consensus. Translated questionnaires undergo a pilot-testing. Suggestions are incorporated into the final questionnaire. Requests for translations originate from the module developers, physicians or pharmaceutical industry, and most translations are performed by professional translators. The translation procedure is managed and supervised by a Translation Coordinator within the EORTC QL Unit in Brussels. Results: To date, the EORTC QLQ-C30 has been translated and validated into more than 60 languages, with further translations in progress. Translations include all major Western, and many African and Asian languages. The following translation problems were encountered: lack of expressions for specific symptoms in various languages, the use of old-fashioned language, recent spelling reforms in several European countries and different priorities of social issues between Western and Eastern cultures. The EORTC measurement system is now registered for use in over 9000 clinical trials worldwide. Conclusions: The EORTC provides strong infrastructure and quality control to produce robust translated questionnaires. Nevertheless, translation problems have been identified. The key to improvements may lie in the particular features and strengths of the group, consisting of researchers from 21 countries representing 25 languages and include the development of simple source versions, the use of advanced computerised tools, rigorous pilot-testing, certification procedures and insights from a unique cross-cultural database of nearly 40,000 questionnaire responses
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