643 research outputs found
An Overview of Methods in the Analysis of Dependent ordered catagorical Data: Assumptions and Implications
Subjective assessments of pain, quality of life, ability etc. measured by rating scales and questionnaires are common in clinical research. The resulting responses are categorical with an ordered structure and the statistical methods must take account of this type of data structure. In this paper we give an overview of methods for analysis of dependent ordered categorical data and a comparison of standard models and measures with nonparametric augmented rank measures proposed by Svensson. We focus on assumptions and issues behind model specifications and data as well as implications of the methods. First we summarise some fundamental models for categorical data and two main approaches for repeated ordinal data; marginal and cluster-specific models. We then describe models and measures for application in agreement studies and finally give a summary of the approach of Svensson. The paper concludes with a summary of important aspects.Dependent ordinal data; GEE; GLMM; Logit; modelling
Comparison of methods in the analysis of dependent ordered catagorical data
Rating scales for outcome variables produce categorical data which are often ordered and measurements from rating scales are not standardized. The purpose of this study is to apply commonly used and novel methods for paired ordered categorical data to two data sets with different properties and to compare the results and the conditions for use of these models. The two applications consist of a data set of inter-rater reliability and a data set from a follow-up evaluation of patients. Standard measures of agreement and measures of association are used. Various loglinear models for paired categorical data using properties of quasi-independence and quasi-symmetry as well as logit models with a marginal modelling approach are used. A nonparametric method for ranking and analyzing paired ordered categorical data is also used. We show that a deeper insight when it comes to disagreement and change patterns may be reached using the nonparametric method and illustrate some problems with standard measures as well as parametric loglinear and logit models. In addition, the merits of the nonparametric method are illustrated.Agreement:ordinal data; ranking; reliability.rating scales
Codes of ethics in Sweden\u27s largest public sector organizations : communicating the intent of the code within the organization
The aim of the study was to examine the ways that public sector organizations in Sweden communicated the intent of their codes of ethics to their employees. Primary data was obtained via a self-administered mail questionnaire distributed to a census of the top 100 organizations. The study identified a range of methods used by organizations to integrate the ethos of codes into corporate culture. These methods included communication of the code, company induction of new staff, consequences for a breach of the code, ethical performance, an ethics ombudsman, the support of whistleblowers, a standing ethics committee, ethics education, and an ethics education committee.Whilst many organizations have instituted ethical behaviour initiatives, activities specifically targeted at exposure, education and support for staff to perform ethically were found to be underdeveloped.<br /
Regionaltågstrafikens effekter: En studie av regionaltågslinjer i Skåne
The focus of this project is on the effects of regional train traffic consisting of Pågatåg and Öresund trains in Skåne, Sweden. The principal effects studied are travelling/commuting by train, population trends in the suburban areas around stations, population distribution in Skåne compared to the rest of the country, development of the labour market regions, changes in the educational level in Skåne compared to the rest of the country, and property price trends after the introduction of regional trains
Ranking programs using black box testing
We present an unbiased method for measuring the relative quality of different solutions to a programming problem. Our method is based on identifying possible bugs from program behaviour through black-box testing. The main motivation for such a method is its use in experimental evaluation of software development methods. We report on the use of our method in a small-scale such experiment, which was aimed at evaluating the effectiveness of property-based testing vs. unit testing in software development. Copyright 2010 ACM
Characterization of Natural Killer Cell Phenotype and Function during Recurrent Human HSV-2 Infection
Human natural killer (NK) cell differentiation, characterized by a loss of NKG2A in parallel with the acquisition of NKG2C, KIRs, and CD57 is stimulated by a number of virus infections, including infection with human cytomegalovirus (CMV), hantavirus, chikungunya virus, and HIV-1. Here, we addressed if HSV-2 infection in a similar way drives NK cell differentiation towards an NKG2A-NKG2C+KIR+CD57+ phenotype. In contrast to infection with CMV, hantavirus, chikungunya virus, and HIV-1, recurrent HSV-2 infection did not yield an accumulation of highly differentiated NK cells in human peripheral blood. This outcome indicates that human HSV-2 infection has no significant imprinting effect on the human NK cell repertoire
Finding Race Conditions in Erlang with Quick Check and PULSE
We address the problem of testing and debugging concurrent, distributed Erlang applications. In concurrent programs, race conditions are a common class of bugs and are very hard to find in practice. Traditional unit testing is normally unable to help finding all race conditions, because their occurrence depends so much on timing. Therefore, race conditions are often found during system testing, where due to the vast amount of code under test, it is often hard to diagnose the error resulting from race conditions. We present three tools (Quick Check, PULSE, and a visualizer) that in combination can be used to test and debug concurrent programs in unit testing with a much better possibility of detecting race conditions. We evaluate our method on an industrial concurrent case study and illustrate how we find and analyze the race conditions
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