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ABSTRACT The topic of this article is pre‐posterior distributions of success or failure. These distributions, determined before a study is run and based on all our assumptions, are what we should believe about the treatment effect if we are told only that the study has been successful, or unsuccessful. I show how the pre‐posterior distributions of success and failure can be used during the planning phase of a study to investigate whether the study is able to discriminate between effective and ineffective treatments. I show how these distributions are linked to the probability of success (PoS), or failure, and how they can be determined from simulations if standard asymptotic normality assumptions are inappropriate. I show the link to the concept of the conditional PoS$$ PoS $$ introduced by Temple and Robertson in the context of the planning of multiple studies. Finally, I show that they can also be constructed regardless of whether the analysis of the study is frequentist or fully Bayesian. [ABSTRACT FROM AUTHOR]

In this article, I extend the use of probability of success calculations, previously developed for fixed sample size studies to group sequential designs (GSDs) both for studies planned to be analyzed by standard frequentist techniques or Bayesian approaches. The structure of GSDs lends itself to sequential learning which in turn allows us to consider how knowledge about the result of an interim analysis can influence our assessment of the study's probability of success. In this article, I build on work by Temple and Robertson who introduced the idea of conditional probability of success, an idea which I also treated in a recent monograph. [ABSTRACT FROM AUTHOR]

When statisticians are uncertain as to which parametric statistical model to use to analyse experimental data, they will often resort to a non‐parametric approach. The purpose of this paper is to provide insight into a simple approach to take when it is unclear as to the appropriate parametric model and plan to conduct a Bayesian analysis. I introduce an approximate, or substitution likelihood, first proposed by Harold Jeffreys in 1939 and show how to implement the approach combined with both a non‐informative and an informative prior to provide a random sample from the posterior distribution of the median of the unknown distribution. The first example I use to demonstrate the approach is a within‐patient bioequivalence design and then show how to extend the approach to a parallel group design. [ABSTRACT FROM AUTHOR]

• South African children lack access to timely paediatric surgical care. • Johannesburg specialist paediatric surgical centres are unable to accommodate all patients referred from lower-level hospitals. • Significant delays exist between referral and arrival of patients at specialist centres. • Lower-level hospitals have been identified for outreach and decentralisation efforts. Paediatric surgery is a centralised service that is provided at only three public sector hospitals in Johannesburg, South Africa. These centres receive an overwhelming number of referrals from over fifty lower-level hospitals. The aim of this study was to analyse referrals to these specialist centres in order to quantify the unmet referred burden of disease and to identify ways in which paediatric surgical access in the region can be improved. A prospective descriptive study was conducted over a 1-year period (01/06/21–31/05/22). All inter-hospital referrals from lower-level hospitals to the three Johannesburg-based specialist centres were analysed. 2394 unique referrals to 3 hospitals were recorded. Five main diagnoses were responsible for 68% of all referrals: neonatal surgical conditions, burns, acute abdomen/bowel obstruction, trauma and symptomatic hernias. 59.7% of all referred patients met criteria for emergency transfer to a specialist unit. 26.7% of these patients, however, were unable to be transferred owing to a lack of bedspace at specialist centres. Transferred patients experienced significant time delays between referral and arrival. Four lower-level hospitals have been identified as possible sites for service expansion. A large unmet paediatric surgical burden of disease has been identified. Lower-level hospitals have been identified that may be suitable for the implementation of decentralisation efforts to improve access to paediatric surgery within the region. V [ABSTRACT FROM AUTHOR]

Children remain the most common victim of burns in Sub-Saharan Africa. This study describes the epidemiology of paediatric burn injury among patients admitted to Chris Hani Baragwanath Academic Hospital. Hospital based cross-sectional, prospective study. 509 patients were admitted to the unit over a 12-month period, with 482 patients included for baseline analysis. 50% of admitted patients were between 15 and 47 months with a median age of 25 months. 58% of participants were male. The predominant mechanism of injury was scalding (84%), in the winter season (32%). The most common site of burn was upper limb (75%). 63% of all admissions received first aid. Among those who received first aid, a described first aid method was provided in 74% of the cases. 226 out of 482 participants (47%) provided sociodemographic information. Access to basic amenities was high, with most admissions coming from households with access to electricity (91%). 90% of caregivers held at least a high school leaving certificate. Migrant caregivers made 19% of the caregivers, which was four times the proportion of foreign nationals counted in the national census. Most admissions (79%) were referrals from other centres as opposed to walk-ins. Severe burns were associated with thermal mechanism of injury, multiple burn sites, and receiving first aid prior to admission. Children under two years of age and children of minority groups are at greatest risk for burn injury and should therefore be targeted for injury prevention strategies and education on appropriate first aid. According to the Journal of pediatric Surgery, this research corresponds to Level II evidence as a prospective study with less than 80% follow-up. ○ What are the main take home messages from this article? • Children under the age of two years and children of minority populations appear to have a disproportionally higher risk for burn injuries than other population groups. • In the community there is inadequate use of appropriate first aid for burn injury. • Suggested places for education about burn injury prevention and first aid prevention could include vaccination centres where the target population frequents. • Identified areas of further research include understanding caregivers, referral patterns and risk factors for severe burns. [ABSTRACT FROM AUTHOR]

Abstract Background The purpose of this research is to develop and evaluate methods for conducting cluster randomised trials in a primary care database that contains electronic patient records for large numbers of family practices. Cluster randomised trials are trials in which the units allocated represent groups of individuals, in this case family practices and their registered patients. Cluster randomised trials often suffer from the limitation that they include too few clusters, leading to problems of insufficient power and only imprecise estimation of the intraclass correlation coefficient, a key design parameter. This difficulty might be overcome by utilising databases that already hold electronic patient records for large numbers of practices. The protocol describes one application: a study of antibiotic prescribing for acute respiratory infection; a second protocol outlines an intervention in a less frequent chronic condition of public health importance, stroke. Methods/Design The objective of the study is to implement a cluster randomised trial to test the effectiveness of an electronic record-based intervention at achieving a reduction in antibiotic prescribing at consultations for respiratory illness in patients aged 18 and 59 years old in intervention family practices as compared with controls. Family practices will be recruited from the practices that presently contribute data to the UK General Practice Research Database (GPRD). Following randomisation, electronic prompts will be installed remotely at intervention practices to promote adherence with evidence-based standards of medical practice. The intervention was developed through qualitative research at non-intervention practices. Data for outcome assessment will be obtained from anonymised electronic patient records that are routinely collected into GPRD. This protocol outlines the proposed study designs, data sources, sample size requirements, analysis methods and dissemination plans. Ethical issues are also discussed. Discussion Results from this study will provide methodological evidence concerning the use of electronic patient records and databases for implementing cluster randomised trials in primary care. The study will also provide substantive findings in respect of electronic record-based interventions to reduce antibiotic prescribing in primary care. Trial Registration Current Controlled Trials ISRCTN 47558792.