We describe a quantitative and comparative review of a selection of European birthweight standards for gestational age for singletons, to enable appropriate choices to be made for clinical and research use. Differences between median values at term across standards in 10 regions and...

Purpose: Observational studies may provide important information on the long-term effects of treatments for epilepsy, but systematic reviews of observational studies may be more prone to heterogeneity and biases. These issues were investigated in a systematic review of non-randomised add-on...

Using individual patient data from five independent surveys, we evaluate regional variations in survival in cerebral palsy. The influence of four important variables measuring disability, which are only partially observed for many cases, are analysed. Results are compared between a naive...

This article introduces the Stata menu-driven program steppedwedge, which calculates detectable differences and power for stepped-wedge randomized trials. The command permits continuous, binary, and rate outcomes (with normal approximations) for comparisons using two-sided tests. The command...

We introduce the Stata menu-driven command clustersampsi, which calculates sample sizes, detectable differences, and power for cluster randomized controlled trials. The command permits continuous, binary, and rate outcomes (with normal approximations) for comparisons of two-sided tests in two...

Aims and Motivation To examine the effect of level of disability on the survival of children with cerebral palsy using a cohort taken from Bristol. The data is subject to, possibly not missing at random (NMAR), unobserved covariate data. Methods A joint survival model for the log-survival times...

In longitudinal and multivariate settings incomplete data, due to missed visits, dropouts or non-return of questionnaires are quite common. A longitudinal trial in which potentially informative missingness occurs is the Collaborative Ankle Support Trial (CAST). The aim of this study is to...

We propose a three-parameter skew-normal distribution, obtained by using hidden truncation on a skew-normal random variable. The hidden truncation framework permits direct interpretation of the model parameters. A link is established between the model and the closed skew-normal distribution.