The glm log-rank test:general linear modeling of log-rank scores as a method of analysis for survival data

The use of general linear modeling (GLM) procedures based on log-rank scores is proposed for the analysis of survival data and compared to standard survival analysis procedures. For the comparison of two groups, this approach performed similarly to the traditional log-rank test. In the case of more complicated designs - without ties in the survival times - the approach was only marginally less powerful than tests from proportional hazards models, and clearly less powerful than a likelihood ratio test for a fully parametric model; however, with ties in the survival time, the approach proved more powerful than tests from Cox's semi-parametric proportional hazards procedure. The method appears to provide a reasonably powerful alternative for the analysis of survival data, is easily used in complicated study designs, avoids (semi-)parametric assumptions, and is quite computationally easy and inexpensive to employ.     

Längsschnittdaten und Mehrebenenanalyse

In the present article a few basic multilevel models for longitudinal data are introduced and applied to the Household Income and Labor Dynamics in Australia Survey 10 (HILDA) for demonstrational purposes. The covered models are adaptions of the random-intercept-only model, the random-intercept models and the random- intercept random-slope model with and without level-1 and level-2 predictors to longitudinal data. The modeling of contextual effects is covered. One particularity in longitudinal data is the fact that persons (level-2) may be regarded as the context of the time-varying observations on level-1. To incorporate the macro-level of sociology, it is necessary to expand the model to a third level. A model with three levels is introduced and in addition a simple growth curve model and a multivariate multilevel model are presented.     

A Model of Engagement Promotion in a Professionally Facilitated Online Intervention for Couples Affected by Breast Cancer

Professionally facilitated web‐based interventions for couples affected by an illness such as cancer are growing in popularity. Attrition rates for such online programs, however, are substantially higher than what is observed in face‐to‐face therapeutic contexts, and lower levels of participant engagement are associated with poorer outcomes. In the present investigation, a task analysis was employed to develop a model of engagement promotion in an online intervention for couples affected by breast cancer called “Couplelinks.” Results indicated that facilitators utilized a variety of meta‐processes, such as humanizing the technology, and associated “eBehaviors,” to maintain three relationships involved in promoting online engagement: (a) between the facilitator and couple; (b) between the intervention and couple; and (c) between the partners within the couple.     

Performance of some multiple testing procedures to compare three doses of a test drug and placebo

A study design with two or more doses of a test drug and placebo is frequently used in clinical drug development. Multiplicity issues arise when there are multiple comparisons between doses of test drug and placebo, and also when there are comparisons of doses with one another. An appropriate analysis strategy needs to be specified in advance to avoid spurious results through insufficient control of Type I error, as well as to avoid the loss of power due to excessively conservative adjustments for multiplicity. For evaluation of alternative strategies with possibly complex management of multiplicity, we compare the performance of several testing procedures through the simulated data that represent various patterns of treatment differences. The purpose is to identify which methods perform better or more robustly than the others and under what conditions. Copyright © 2005 John Wiley & Sons, Ltd.     

Methods for clarifying criteria for study continuation at interim analysis

In monitoring clinical trials, the question of futility, or whether the data thus far suggest that the results at the final analysis are unlikely to be statistically successful, is regularly of interest over the course of a study. However, the opposite viewpoint of whether the study is sufficiently demonstrating proof of concept (POC) and should continue is a valuable consideration and ultimately should be addressed with high POC power so that a promising study is not prematurely terminated. Conditional power is often used to assess futility, and this article interconnects the ideas of assessing POC for the purpose of study continuation with conditional power, while highlighting the importance of the POC type I error and the POC type II error for study continuation or not at the interim analysis. Methods for analyzing subgroups motivate the interim analyses to maintain high POC power via an adjusted interim POC significance level criterion for study continuation or testing against an inferiority margin. Furthermore, two versions of conditional power based on the assumed effect size or the observed interim effect size are considered. Graphical displays illustrate the relationship of the POC type II error for premature study termination to the POC type I error for study continuation and the associated conditional power criteria.     

Corporate lobbying: Role perceptions and perceived influence on political decisions of public affairs professionals

This study aims to provide insight into public affairs professionals’ role conceptions and perceived influence on political decision making. We conducted a quantitative online survey with 238 corporate public affairs professionals in Germany who worked either “in-house” at a corporation, for an industry association, or in a public affairs consultancy firm. Based on their main stakeholder orientation (clients, political actors, or society) and primary objectives (mediator, expert, or advocate), a cluster analysis categorized the professionals into four main roles: persuaders, advisors, coordinators, and mediators. Although acting in line with ethical norms and being transparent about their practices were deemed important for all roles, there were differences regarding the balancing of positions and loyalty toward the client. Finally, a regression analysis showed that financial resources, information sovereignty, and ethical considerations were the strongest predictors of public affairs professionals’ perceived influence on political decisions. Implications and avenues for future research are discussed.     

Potential impact of COVID-19 on ongoing clinical trials: a simulation study with the neurological Yale Global Tic Severity Scale based on the CANNA-TICS study

The COVID-19 pandemic has manifold impacts on clinical trials. In response, drug regulatory agencies and public health bodies have issued guidance on how to assess potential impacts on ongoing clinical trials and stress the importance of a risk-assessment as a pre-requisite for modifications to the clinical trial conduct. This article presents a simulation study to assess the impact on the power of an ongoing clinical trial without the need to unblind trial data and compromise trial integrity. In the context of the CANNA-TICS trial, investigating the effect of nabiximols on reducing the total tic score of the Yale Global Tic Severity Scale (YGTSS-TTS) in patients with chronic tic disorders and Tourette syndrome, the impact of the two COVID-19 related intercurrent events handled by a treatment policy strategy is investigated using a multiplicative and additive data generating model. The empirical power is examined for the analysis of the YGTSS-TTS as a continuous and dichotomized endpoint using analysis techniques adjusted and unadjusted for the occurrence of the intercurrent event. In the investigated scenarios, the simulation studies showed that substantial power losses are possible, potentially making sample size increases necessary to retain sufficient power. However, we were also able to identify scenarios with only limited loss of power. By adjusting for the occurrence of the intercurrent event, the power loss could be diminished to different degrees in most scenarios. In summary, the presented risk assessment approach may support decisions on trial modifications like sample size increases, while maintaining trial integrity.     

A Basic Demonstration of the [-1, 1] Range for the Correlation Coefficient

The structure of the variance of linear functions of two variables is used to show that the correlation coefficient lies in the range [-1, 1]. It also allows the role of the correlation coefficient in linear regression to be described.     

A multistage analysis strategy for a clinical trial to assess successively more stringent criteria for a primary endpoint with a low event rate

This paper describes how a multistage analysis strategy for a clinical trial can assess a sequence of hypotheses that pertain to successively more stringent criteria for excess risk exclusion or superiority for a primary endpoint with a low event rate. The criteria for assessment can correspond to excess risk of an adverse event or to a guideline for sufficient efficacy as in the case of vaccine trials. The proposed strategy is implemented through a set of interim analyses, and success for one or more of the less stringent criteria at an interim analysis can be the basis for a regulatory submission, whereas the clinical trial continues to accumulate information to address the more stringent, but not futile, criteria. Simulations show that the proposed strategy is satisfactory for control of type I error, sufficient power, and potential success at interim analyses when the true relative risk is more favorable than assumed for the planned sample size. Copyright © 2013 John Wiley & Sons, Ltd.     

激励机制四原则

成功有效的激励机制必须把员工个人利益与公司集体利益统一起来。如果奖励的结果对员工有益,那么也必须对公司有益,反之亦然。如果奖励的结果对公司有害,则必然也对员工有害。这在遵纪守法的各个方面表现得尤为突出。