Rating versus ranking of values in cross-national research

rating;ranking

Toward adaptive radiotherapy for head and neck patients: Uncertainties in dose warping due to the choice of deformable registration algorithm.

The aims of this work were to evaluate the performance of several deformable image registration (DIR) algorithms implemented in our in-house software (NiftyReg) and the uncertainties inherent to using different algorithms for dose warping

Identifying Unknown Response Styles: A Latent-Class Bilinear Multinomial Logit Model

Respondents can vary significantly in the way they use rating scales. Specifically, respondents can exhibit varying degrees of response style, which threatens the validity of the responses. The purpose of this article is to investigate to what extent rating scale responses show response style and substantive content of the item. The authors develop a novel model that accounts for possibly unknown kinds of response styles, content of the items, and background characteristics of respondents. By imposing a bilinear structure on the parameters of a multinomial logit model, the authors can visually distinguish the effects on the response behavior of both the characteristics of a respondent and the content of the item. This approach is combined with finite mixture modeling, so that two separate segmentations of the respondents are obtained: one for response style and one for item content. This latent-class bilinear multinomial logit (LC-BML) model is applied to a cross-national data set. The results show that item content is highly influential in explaining response behavior and reveal the presence of several response styles, including the prominent response styles acquiescence and extreme response style.multinomial logit model;visualization;segmentation;cross-cultural research;response style

Risk Preference Smoothness and the APT

Attitudes of risk aversion and diversification preference are closely linked to the degree of smoothness of the underlying preference relation over monetary risks, represented in terms of the first and second variations of the preference functional in the direction of incremental risks, evaluated at an initial portfolio. Under general maintained assumptions, "exact" and "approximate" versions of the Arbitrage Pricing Theory (APT) may be derived respectively from first and second-degree smoothness of risk preferences among investors in a competitive, finite asset market

Optimal Regulator Transparency

Private investment activity is regulated by two semi-independent agencies: an enforcement authority and an appeals authority. Once undertaken, an investment project may be interdicted by the enforcement authority before its final payoff is realized. The investor may refer an interdiction to the appeals authority, who upholds or voids the interdiction according to a privately known rule of law. The appeals authority determines the degree of regulatory transparency by issuing more or less revealing guidelines describing the operation of the rule of law in various circumstances. In this setting, the appeals authority maximizes its ability to extract rents from investors by issuing weakly differentiated guidelines which yield the highest possible rate of interdiction by the enforcement authority, together with the highest possible likelihood that interdiction will be overturned on appeal

Regulatory Ambiguity and Corruption

Corruption "in the fabric" of a regulatory system refers to a situation in which a regulatory agency seeks to extract rents for itself by interpreting and enforcing its statutory authority in an ambiguous manner. Regulatory ambiguity is associated with the creation of superfluous and apparently random loopholes which affect private agents under circumstances which are difficult to predict, and hence hard to avoid. This paper examines the role of regulatory authority by means of a model in which the regulatory authority extracts a fee for enforcing or voiding private agreements, in light of circumstances which have occurred after the agreement was formed, according to a system of rules which can be either ambiguous or clear

The potential impact of CT-MRI matching on tumor volume delineation in advanced head and neck cancer

To study the potential impact of the combined use of CT and MRI scans on the Gross Tumor Volume (GTV) estimation and interobserver variation. Four observers outlined the GTV in six patients with advanced head and neck cancer on CT, axial MRI, and coronal or sagittal MRI. The MRI scans were subsequently matched to the CT scan. The interobserver and interscan set variation were assessed in three dimensions. The mean CT derived volume was a factor of 1.3 larger than the mean axial MRI volume. The range in volumes was larger for the CT than for the axial MRI volumes in five of the six cases. The ratio of the scan set common (i.e., the volume common to all GTVs) and the scan set encompassing volume (i.e., the smallest volume encompassing all GTVs) was closer to one in MRI (0.3-0.6) than in CT (0.1-0.5). The rest volumes (i.e., the volume defined by one observer as GTV in one data set but not in the other data set) were never zero for CT vs. MRI nor for MRI vs. CT. In two cases the craniocaudal border was poorly recognized on the axial MRI but could be delineated with a good agreement between the observers in the coronal/sagittal MRI. MRI-derived GTVs are smaller and have less interobserver variation than CT-derived GTVs. CT and MRI are complementary in delineating the GTV. A coronal or sagittal MRI adds to a better GTV definition in the craniocaudal directio