Cluster randomized clinical trials in orthodontics: design, analysis and reporting issues

Cluster randomized trials (CRTs) use as the unit of randomization clusters, which are usually defined as a collection of individuals sharing some common characteristics. Common examples of clusters include entire dental practices, hospitals, schools, school classes, villages, and towns. Additionally, several measurements (repeated measurements) taken on the same individual at different time points are also considered to be clusters. In dentistry, CRTs are applicable as patients may be treated as clusters containing several individual teeth. CRTs require certain methodological procedures during sample calculation, randomization, data analysis, and reporting, which are often ignored in dental research publications. In general, due to similarity of the observations within clusters, each individual within a cluster provides less information compared with an individual in a non-clustered trial. Therefore, clustered designs require larger sample sizes compared with non-clustered randomized designs, and special statistical analyses that account for the fact that observations within clusters are correlated. It is the purpose of this article to highlight with relevant examples the important methodological characteristics of cluster randomized designs as they may be applied in orthodontics and to explain the problems that may arise if clustered observations are erroneously treated and analysed as independent (non-clustered).

Cancer, meta-analysis and reporting biases: the case of erythropoiesis-stimulating agents.

Reporting and publication bias is a well-known problem in meta-analysis and healthcare research. In 2002 we conducted a meta-analysis on the effects of erythropoiesis-stimulating agents (ESAs) on overall survival in cancer patients, which suggested some evidence for improved survival in patients receiving ESAs compared with controls. However, a meta-analysis of individual patient data conducted several years later showed the opposite of our first meta-analysis, that is, evidence for increased on-study mortality and reduced overall survival in cancer patients receiving ESAs. We aimed to determine whether the results of our first meta-analysis could have been affected by publication and reporting biases and, if so, whether timely access to clinical study reports and individual patient data could have prevented this. We conducted a hypothetical meta-analysis for overall survival including all studies and study data that could have been available in 2002, at the time when we conducted our first meta-analysis. Compared with our original meta-analysis, which suggested an overall survival benefit for cancer patients receiving ESAs [hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.67‒0.99], our hypothetical meta-analysis based on the results of all studies conducted at the time of the first analysis did not show evidence for a beneficial effect of ESAs on overall survival (HR 0.97, 95% CI 0.83‒1.12). Thus we have to conclude that our first meta-analysis showed misleading overall survival benefits due to publication and reporting biases, which could have been prevented by timely access to clinical study reports and individual patient data. Unrestricted access to clinical study protocols including amendments, clinical study reports and individual patient data is needed to ensure timely detection of both beneficial and harmful effects of healthcare interventions.

Disclosing and reporting medical errors: Cross-sectional survey of Swiss anaesthesiologists.

BACKGROUND There is limited research on anaesthesiologists' attitudes and experiences regarding medical error communication, particularly concerning disclosing errors to patients. OBJECTIVE To characterise anaesthesiologists' attitudes and experiences regarding disclosing errors to patients and reporting errors within the hospital, and to examine factors influencing their willingness to disclose or report errors. DESIGN Cross-sectional survey. SETTING Switzerland's five university hospitals' departments of anaesthesia in 2012/2013. PARTICIPANTS Two hundred and eighty-one clinically active anaesthesiologists. MAIN OUTCOME MEASURES Anaesthesiologists' attitudes and experiences regarding medical error communication. RESULTS The overall response rate of the survey was 52% (281/542). Respondents broadly endorsed disclosing harmful errors to patients (100% serious, 77% minor errors, 19% near misses), but also reported factors that might make them less likely to actually disclose such errors. Only 12% of respondents had previously received training on how to disclose errors to patients, although 93% were interested in receiving training. Overall, 97% of respondents agreed that serious errors should be reported, but willingness to report minor errors (74%) and near misses (59%) was lower. Respondents were more likely to strongly agree that serious errors should be reported if they also thought that their hospital would implement systematic changes after errors were reported [(odds ratio, 2.097 (95% confidence interval, 1.16 to 3.81)]. Significant differences in attitudes between departments regarding error disclosure and reporting were noted. CONCLUSION Willingness to disclose or report errors varied widely between hospitals. Thus, heads of department and hospital chiefs need to be aware of the importance of local culture when it comes to error communication. Error disclosure training and improving feedback on how error reports are being used to improve patient safety may also be important steps in increasing anaesthesiologists' communication of errors.

Pre-Election Positions and Voting Behaviour in Parliament: Consistency among Swiss MPs

This article examines the determinants of positional incongruence between pre-election statements and post-election behaviour in the Swiss parliament between 2003 and 2009. The question is examined at the individual MP level, which is appropriate for dispersion-of-powers systems like Switzerland. While the overall rate of political congruence reaches about 85%, a multilevel logit analysis detects the underlying factors which push or curb a candidate's propensity to change his or her mind once elected. The results show that positional changes are more likely when (1) MPs are freshmen, (2) individual voting behaviour is invisible to the public, (3) the electoral district magnitude is not small, (4) the vote is not about a party's core issue, (5) the MP belongs to a party which is located in the political centre, and (6) if the pre-election statement dissents from the majority position of the legislative party group. Of these factors, the last one is paramount.

Planning and reporting of quality-of-life outcomes in cancer trials.

BACKGROUND Information about the impact of cancer treatments on patients' quality of life (QoL) is of paramount importance to patients and treating oncologists. Cancer trials that do not specify QoL as an outcome or fail to report collected QoL data, omit crucial information for decision making. To estimate the magnitude of these problems, we investigated how frequently QoL outcomes were specified in protocols of cancer trials and subsequently reported. DESIGN Retrospective cohort study of RCT protocols approved by six research ethics committees in Switzerland, Germany, and Canada between 2000 and 2003. We compared protocols to corresponding publications, which were identified through literature searches and investigator surveys. RESULTS Of the 173 cancer trials, 90 (52%) specified QoL outcomes in their protocol, 2 (1%) as primary and 88 (51%) as secondary outcome. Of the 173 trials, 35 (20%) reported QoL outcomes in a corresponding publication (4 modified from the protocol), 18 (10%) were published but failed to report QoL outcomes in the primary or a secondary publication, and 37 (21%) were not published at all. Of the 83 (48%) trials that did not specify QoL outcomes in their protocol, none subsequently reported QoL outcomes. Failure to report pre-specified QoL outcomes was not associated with industry sponsorship (versus non-industry), sample size, and multicentre (versus single centre) status but possibly with trial discontinuation. CONCLUSIONS About half of cancer trials specified QoL outcomes in their protocols. However, only 20% reported any QoL data in associated publications. Highly relevant information for decision making is often unavailable to patients, oncologists, and health policymakers.

Ascertainment, meta-analysis and reporting of adverse reactions in clinical trials of antibiotics

The ascertainment and analysis of adverse reactions to investigational agents presents a significant challenge because of the infrequency of these events, their subjective nature and the low priority of safety evaluations in many clinical trials. A one year review of antibiotic trials published in medical journals demonstrates the lack of standards in identifying and reporting these potentially fatal conditions. This review also illustrates the low probability of observing and detecting rare events in typical clinical trials which include fewer than 300 subjects. Uniform standards for ascertainment and reporting are suggested which include operational definitions of study subjects. Meta-analysis of selected antibiotic trials using multivariate regression analysis indicates that meaningful conclusions may be drawn from data from multiple studies which are pooled in a scientifically rigorous manner. ^

An Efficient Multiple Object Detection and Tracking Framework for Automatic Counting and Video Surveillance Applications

Automatic visual object counting and video surveillance have important applications for home and business environments, such as security and management of access points. However, in order to obtain a satisfactory performance these technologies need professional and expensive hardware, complex installations and setups, and the supervision of qualified workers. In this paper, an efficient visual detection and tracking framework is proposed for the tasks of object counting and surveillance, which meets the requirements of the consumer electronics: off-the-shelf equipment, easy installation and configuration, and unsupervised working conditions. This is accomplished by a novel Bayesian tracking model that can manage multimodal distributions without explicitly computing the association between tracked objects and detections. In addition, it is robust to erroneous, distorted and missing detections. The proposed algorithm is compared with a recent work, also focused on consumer electronics, proving its superior performance.

Study and analysis of the Leap Motion sensor and the Software Development Kit (SDK) for the implementation of visual Human Computer Interfaces

En este proyecto, se presenta un informe técnico sobre la cámara Leap Motion y el Software Development Kit correspondiente, el cual es un dispositivo con una cámara de profundidad orientada a interfaces hombre-máquina. Esto es realizado con el propósito de desarrollar una interfaz hombre-máquina basada en un sistema de reconocimiento de gestos de manos. Después de un exhaustivo estudio de la cámara Leap Motion, se han realizado diversos programas de ejemplo con la intención de verificar las capacidades descritas en el informe técnico, poniendo a prueba la Application Programming Interface y evaluando la precisión de las diferentes medidas obtenidas sobre los datos de la cámara. Finalmente, se desarrolla un prototipo de un sistema de reconocimiento de gestos. Los datos sobre la posición y orientación de la punta de los dedos obtenidos de la Leap Motion son usados para describir un gesto mediante un vector descriptor, el cual es enviado a una Máquina Vectores Soporte, utilizada como clasificador multi-clase.

Memo to Merkel: Post-election Germany and Europe. Bruegel Policy Brief 2013/05, 24 September 2013

Recent economic data points to the seeds of an economic recovery in the European Union. However, significant risks remain and bold policies are still needed. There are three central risks. Competitiveness adjustment is incomplete, casting doubt on the sustainability of public debt. Banking remains unstable and fragmented along national lines, resulting in unfavorable financial conditions, which further erode growth, job creation and competitiveness. Rising unemployment, especially among the young, is inequitable, unjust and politically risky. Germany has a central role to play in addressing these risks. The new German government should work on three priorities: Domestic economic policy should be more supportive of growth and adjustment, with higher public investment, a greater role for high-value added services, and more supportive immigration policy. Germany should support a meaningful banking union with a centralised resolution mechanism requiring a transfer of sovereignty to Europe for all countries including Germany. The establishment of a private investment initiative combined with a European Youth Education Fund and labour market reforms should be promoted. Building on these priorities, a significant deepening of the euro area is needed, with a genuine transfer of sovereignty, stronger institutions and democratically legitimate decision-making structures in areas of common policy.

Puerto Rico : Commonwealth election law and its application to a political status referendum : report to the Chairman, Committee on Energy and Natural Resources, U.S. Senate /

Running title : Puerto Rico's status referendum.