Design, analysis and presentation of factorial randomised controlled trials

BackgroundThe evaluation of more than one intervention in the same randomised controlled trial can be achieved using a parallel group design. However this requires increased sample size and can be inefficient, especially if there is also interest in considering combinations of the interventions. An alternative may be a factorial trial, where for two interventions participants are allocated to receive neither intervention, one or the other, or both. Factorial trials require special considerations, however, particularly at the design and analysis stages.DiscussionUsing a 2 × 2 factorial trial as an example, we present a number of issues that should be considered when planning a factorial trial. The main design issue is that of sample size. Factorial trials are most often powered to detect the main effects of interventions, since adequate power to detect plausible interactions requires greatly increased sample sizes. The main analytical issues relate to the investigation of main effects and the interaction between the interventions in appropriate regression models. Presentation of results should reflect the analytical strategy with an emphasis on the principal research questions. We also give an example of how baseline and follow-up data should be presented. Lastly, we discuss the implications of the design, analytical and presentational issues covered.SummaryDifficulties in interpreting the results of factorial trials if an influential interaction is observed is the cost of the potential for efficient, simultaneous consideration of two or more interventions. Factorial trials can in principle be designed to have adequate power to detect realistic interactions, and in any case they are the only design that allows such effects to be investigated

Educational Outcomes of Small-Group Discussion Versus Traditional Lecture Format in Dental Students\u27 Learning and Skills Acquisition.

The aim of this prospective quantitative study was to compare the effect of different instructional formats on dental students\u27 skills and knowledge acquisition for access cavity preparation. All first-year dental students were invited to participate in this study conducted during the four consecutive two-week endodontic rotation courses at the University of the Pacific Arthur A. Dugoni School of Dentistry in spring semester 2015. Four alphabetically distributed intact groups of students were randomly allocated to two groups (n=70 each) that participated in either small-group discussion or a traditional lecture on access preparation. The first outcome measure was skill acquisition, measured by the quality of access cavities prepared in extracted teeth at the conclusion of the session. Two blinded raters scored direct observations on a continuous scale. Knowledge, the second outcome measure, was scored with a multiple-choice and open-ended question test at the end of each two-week session. Data were obtained for 134 of the 140 students, for a 96% response rate. The results showed that students in the small-group discussion groups scored significantly higher than those in the lecture groups when skill performance was tested (p=8.9 × 10(-7)). However, no significant differences were found in the acquisition of knowledge between the two groups on the written test. Active student participation was significantly related to improved manual skill acquisition, but the format of the session does not seem to have had a direct influence on acquired knowledge

Paracetamol plus ibuprofen for the treatment of fever in children (PITCH): randomised controlled trial

Objective To investigate whether paracetamol (acetaminophen) plus ibuprofen are superior to either drug alone for increasing time without fever and the relief of fever associated discomfort in febrile children managed at home

Medicine dosing by weight in the home: Can parents accurately weigh preschool children? A method comparison study

Objective: To determine the accuracy with which parents can estimate preschool children's weight using home scales in order to calculate antipyretic dose. Design: Cross-sectional, method comparison study. Setting and participants: 156 preschool children aged 6 months to 6 years recruited from primary care and the community to an antipyretic strategies trial and managed at home. Comparison and outcome measures: Research nurse weight estimate using Seca 835-2 digital paediatric scales compared with parental weight estimate using usual home scales. Results: Parents of 62 (40%) preschool children had home scales. Research scale estimated weights were heavier than home scale weight estimates, with a mean difference of 0.41 kg (95% CI -0.24 to 0.74 kg), with 95% limits of agreement of -2.44 to 1.47 kg. Conclusion: Weight can be estimated accurately enough to calculate antipyretic medicine doses by the minority of parents having scales that can be used to estimate their child's weight

Reporting of factorial trials of complex interventions in community settings: a systematic review

<p>Abstract</p> <p>Background</p> <p>Standards for the reporting of factorial randomised trials remain to be established. We aimed to review the quality of reporting of methodological aspects of published factorial trials of complex interventions in community settings.</p> <p>Methods</p> <p>We searched MEDLINE, EMBASE, PsychInfo and the Cochrane Controlled Trials Register to identify factorial randomised trials of complex interventions in community settings from January 2000 to August 2009. We also conducted a citation search of two review papers published in 2003. Data were extracted by two reviewers on 22 items relating to study design, analysis and presentation.</p> <p>Results</p> <p>We identified 5941 unique titles, from which 116 full papers were obtained and 76 were included in the review. The included trials reflected a broad range of target conditions and types of intervention. The median sample size was 400 (interquartile range 191-1001). Most (88%) trials employed a 2 × 2 factorial design. Few trials (21%) explicitly stated the rationale for using a factorial design. Reporting of aspects of design, analysis or presentation specific to factorial trials was variable, but there was no evidence that reporting of these aspects was different for trials published before or after 2003. However, for CONSORT items that apply generally to the reporting of all trials, there was some evidence that later studies were more likely to report employing an intention-to-treat (ITT) approach (78% vs 52%), present appropriate between-group estimates of effect (88% vs 63%), and present standard errors or 95% confidence intervals for such estimates (78% vs 56%). Interactions between interventions and some measure of the precision associated with such effects were reported in only 14 (18%) trials.</p> <p>Conclusions</p> <p>Reports of factorial trials of complex interventions in community settings vary in the amount of information they provide regarding important methodological aspects of design and analysis. This variability supports the extension of CONSORT guidelines to include the specific reporting of factorial trials.</p

No sex scandals please, we're French: French attitudes towards politicians' public and private conduct

The notion of distinct ‘public’ and ‘private’ spheres underpins much normative and practical engagement with political misconduct. What is less clear is whether citizens draw distinctions between misdemeanours in the ‘public’ and ‘private’ spheres, and whether they judge these in systematically different ways. This paper explores attitudes to political misconduct in France. French citizens are often said to be particularly relaxed about politicians’ private affairs, but there has been little empirical evidence for this proposition. Drawing on original survey data, this paper demonstrates clearly that French citizens draw a sharp distinction between politicians’ public and private transgressions, and are more tolerant of the latter

The frequency distribution of presenting symptoms in children aged six months to six years to primary care.

Primary care providers and researchers wishing to estimate study recruitment rates need estimates of illness frequency in primary care. Previous studies of children's symptoms have found that presentations are most common for the symptoms: cough, fever, earache, rash, diarrhoea and vomiting. Since 2000, primary care provision in the United Kingdom has changed with the introduction of Walk-in-Centres (WICs) and new Out of Hours (OoHs) providers. To describe the type and frequency of parent-reported presenting symptoms at a range of primary care sites between 2005 and 2007. Parent-reported presenting symptoms, recorded in their own words, were extracted from data collected from all children aged six months to six years during recruitment to a randomised controlled trial. Presenting symptoms were coded and presented as frequency per 100 'consulting sessions' by type of primary care site. Results were evaluated from 2491 episodes of illness at 35 sites. When grouped by primary care site, respiratory symptoms were the most common at OoHs centres, the WIC and general practitioner (GP) surgeries. Trauma symptoms were common in the Emergency Department, but unexpectedly, diarrhoea and vomiting were more common in the Emergency Department and skin presenting symptoms more common at the WIC than at GP sites. We report the relative frequency of acute symptoms by type of primary care provider. These data may be useful to those planning recruitment to primary care paediatric studies and policy makers for planning primary care service provision

IMpower030: Phase III study evaluating neoadjuvant treatment of resectable stage II-IIIB non-small cell lung cancer (NSCLC) with atezolizumab (atezo) + chemotherapy

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Edge-Magnetoplasmon Wave-Packet Revivals in the Quantum Hall Effect

The quantum Hall effect is necessarily accompanied by low-energy excitations localized at the edge of a two-dimensional electron system. For the case of electrons interacting via the long-range Coulomb interaction, these excitations are edge magnetoplasmons. We address the time evolution of localized edge-magnetoplasmon wave packets. On short times the wave packets move along the edge with classical E cross B drift. We show that on longer times the wave packets can have properties similar to those of the Rydberg wave packets that are produced in atoms using short-pulsed lasers. In particular, we show that edge-magnetoplasmon wave packets can exhibit periodic revivals in which a dispersed wave packet reassembles into a localized one. We propose the study of edge-magnetoplasmon wave packets as a tool to investigate dynamical properties of integer and fractional quantum-Hall edges. Various scenarios are discussed for preparing the initial wave packet and for detecting it at a later time. We comment on the importance of magnetoplasmon-phonon coupling and on quantum and thermal fluctuations.Comment: 18 pages, RevTex, 7 figures and 2 tables included, Fig. 5 was originally 3Mbyte and had to be bitmapped for submission to archive; in the process it acquired distracting artifacts, to upload the better version, see http://physics.indiana.edu/~uli/publ/projects.htm