Sample size re‐estimation incorporating prior information on a nuisance parameter

Prior information is often incorporated informally when planning a clinical trial. Here, we present an approach on how to incorporate prior information, such as data from historical clinical trials, into the nuisance parameter–based sample size re‐estimation in a design with an internal pilot study. We focus on trials with continuous endpoints in which the outcome variance is the nuisance parameter. For planning and analyzing the trial, frequentist methods are considered. Moreover, the external information on the variance is summarized by the Bayesian meta‐analytic‐predictive approach. To incorporate external information into the sample size re‐estimation, we propose to update the meta‐analytic‐predictive prior based on the results of the internal pilot study and to re‐estimate the sample size using an estimator from the posterior. By means of a simulation study, we compare the operating characteristics such as power and sample size distribution of the proposed procedure with the traditional sample size re‐estimation approach that uses the pooled variance estimator. The simulation study shows that, if no prior‐data conflict is present, incorporating external information into the sample size re‐estimation improves the operating characteristics compared to the traditional approach. In the case of a prior‐data conflict, that is, when the variance of the ongoing clinical trial is unequal to the prior location, the performance of the traditional sample size re‐estimation procedure is in general superior, even when the prior information is robustified. When considering to include prior information in sample size re‐estimation, the potential gains should be balanced against the risks.     

Attitudes of social work students towards older people

Demographic ageing is a challenge for many countries. Even though Turkey has a relatively younger demographic composition, the proportion of the older people (65+) within the population is rapidly increasing. Within this framework, older people are becoming more important clients for both social work students and social workers in Turkey. This study aims to reveal the attitudes of social work students towards older people and determine the various factors that affect their views on older persons. In the scope of the project, Kogan's Attitude Towards Old People Scale was applied to 419 social work undergraduate students at a university located in Central Anatolia. The findings showed that social work students scored a mean of 130.96 and they generally had positive attitudes towards older people. The correlation between year of study, gender and age was not statistically significant. However, having lived mostly in urban areas was positively correlated with the mean Kogan scores and this finding was found to be statistically significant. Exposure to personal contact with older people at both the personal and professional levels was influential in shaping attitudes about the older people.     

Optimal acceptance sampling for modules F and F1 of the European Measuring Instruments Directive

ABSTRACT

Acceptance sampling plans offered by ISO 2859-1 are far from optimal under the conditions for statistical verification in modules F and F1 as prescribed by Annex II of the Measuring Instruments Directive (MID) 2014/32/EU, resulting in sample sizes that are larger than necessary. An optimised single-sampling scheme is derived, both for large lots using the binomial distribution and for finite-sized lots using the exact hypergeometric distribution, resulting in smaller sample sizes that are economically more efficient while offering the full statistical protection required by the MID.     

Multi-neighborhood based iterated tabu search for routing and wavelength assignment problem

The routing and wavelength assignment problem (RWA) has shown to be NP-hard if the wavelength continuity constraint and the objective of minimizing the number of wavelengths are considered. This paper introduces a multi-neighborhood based iterated tabu search algorithm (MN-ITS), which consists of three neighborhoods with a unified incremental evaluation method, to solve the min-RWA problem. The proposed MN-ITS algorithm is tested on a set of widely studied real world instances as well as a set of challenging random ones in the literature. Comparison with other reference algorithms shows that the MN-ITS algorithm is able to improve five best upper bounds obtained by other competitive reference algorithms in the literature. This paper also presents an analysis to show the significance of the unified incremental evaluation technique and the combination of multiple neighborhoods.     

The no-wait job shop with regular objective: a method based on optimal job insertion

The no-wait job shop problem (NWJS-R) considered here is a version of the job shop scheduling problem where, for any two operations of a job, a fixed time lag between their starting times is prescribed. Also, sequence-dependent set-up times between consecutive operations on a machine can be present. The problem consists in finding a schedule that minimizes a general regular objective function. We study the so-called optimal job insertion problem in the NWJS-R and prove that this problem is solvable in polynomial time by a very efficient algorithm, generalizing a result we obtained in the case of a makespan objective. We then propose a large neighborhood local search method for the NWJS-R based on the optimal job insertion algorithm and present extensive numerical results that compare favorably with current benchmarks when available.     

The effect of accounting standards on Big Bath behavior

This paper investigates the influence of accounting standards on systematic earnings understatement. To isolate the effect of reporting regulations from those of other institutional drivers of earnings management, Holthausen (2003) proposes analyzing reporting practices in a country undergoing a transition in accounting standards. We respond to this call by analyzing earnings management practices of large German-listed companies before and after their transitions from German GAAP to IFRS. Specifically, we focus on Big Bath behavior following Chief Financial Officer turnovers between 1999 and 2006. Our findings provide evidence of the effect of accounting standards on the existence of this particular earnings understatement pattern. However, while we detect Big Bath behavior for our sample of German GAAP firms, we find no such indication for those firms reporting under IFRS. Controlling for alternative explanations such as self-selection bias does not change our findings. We conclude that accounting standards seem to have a considerable influence on earnings management behavior, independent of managers’ and auditors’ incentives.     

Congregational Composition and Explanations for Racial Inequality Among Black Religious Affiliates

Prior research suggests that congregational characteristics are associated with the racial attitudes of Black churchgoers. This study examines the relationship between congregational diversity and beliefs about the Black/White socioeconomic gap among Black religious adherents. Drawing upon pooled data from the General Social Survey and the National Congregations Study, we fit binary logistic regression models to estimate the association between congregational diversity and the explanations of Black/White economic inequality among Black religious adherents. Findings from our study reveal that congregational diversity is one factor that accounts for intragroup differences in racial attitudes among Black religious affiliates. Relative to Blacks that attend religious services in overwhelmingly Black congregations, Blacks that attend religious services in congregations that are overwhelmingly White are significantly less likely to attribute Black/White socioeconomic gaps to a lack of educational opportunities. Our study demonstrates that congregational diversity is a source of intragroup variation in racial attitudes among Black religious affiliates, which may attenuate the ability of such congregations to bridge racial divisions.     

More than Subversion: Four Strategies for the Dominated

This article asks what strategies are available to dominated actors in fields of cultural production. Using archival and biographical materials on Ottoman/Turkish women intellectuals, we show that they effectively used, depending on their social and cultural capital and their past practices, at least four strategies. Apart from the well-theorized strategy of subversion, they could also deploy acquiescence, collaboration, and defiance. These four strategies, we argue, constitute a two-dimensional space defined by loyalty vs. resistance on one hand and the overtness vs. covertness of loyalty or resistance on the other. While much of this space is best understood in terms of reciprocal social exchange, the assumptions of exchange break down in the case of overt resistance, showing that strategy goes beyond negotiation and that the understanding of power as always-already implicated with resistance has limits.     

Negotiating Symbolic Boundaries in Conflict Resolution: Religion and Ethnicity in Turkey’s Kurdish Conflict

This article is an inquiry into understanding why supranational religious identity often fails to act as a conflict resolution tool in religiously homogenous ethnic conflicts. Narrowing its focus down to the role of religious elites as potential peacemakers in such conflict zones, it proposes the divergence in their conceptualizations of religious and ethnic identities as an explanatory factor. Building on 62 in-depth interviews conducted in Turkey with Sunni Muslim Kurdish and Turkish religious elites, it identifies a three-fold typology of religious and ethnic identities, as conceptualized by these elites: 1) religio-ethnic; 2) ethno-religious; 3) religious. After exemplifying each category with interview data it demonstrates the role these distinctions play in preventing the successful implementation of “Muslim fraternity” as a solution to the Kurdish conflict in Turkey. With these findings, the article contributes to both the literature on religion in conflict resolution and that on identity formation and boundary making. While it invites the former to turn its gaze from macro-level structural factors to meso- and micro-level cultural factors in analyzing religious elite involvement in conflict resolution, it invites the latter to stop employing “ethnicity” as an all-encompassing term (that covers a vast array of identity markers including religion) and focus, instead, on the gradations between religion and ethnicity as sources of identity.