Background: Multiple imputation (MI) provides an effective approach to handle missing covariate data within prognostic modelling studies, as it can properly account for the missing data uncertainty. The multiply imputed datasets are each analysed using standard prognostic modelling techniques to...

The Cox proportional hazards model has been used extensively in medicine over the last 40 years. A popular application is to develop a multivariable prediction model, often a prognostic model to predict the clinical outcome of patients with a particular disorder from "baseline" factors measured...

Royston (2014, Stata Journal 14: 738–755) explained how a popular application of the Cox proportional hazards model "is to develop a multivariable prediction model, often a prognostic model to predict the future clinical outcome of patients with a particular disorder from 'baseline' factors...

I provide a new programming tool, cmpute, to manage conveniently the creation of a new variable or the replacement of an existing variable interactively or within a Stata program. Copyright 2013 by StataCorp LP.

We consider how to represent sigmoid-type regression relationships in a practical and parsimonious way. A pure sigmoid relationship has an asymptote at both ends of the range of a continuous covariate. Curves with a single asymptote are also important in practice. Many smoothers, such as...

I provide a new tool (marginscontplot) for plotting the marginal effect of continuous covariates in regression models. The plots may be univariate or according to levels or user-selected values of a second covariate. Nonlinear relationships involving transformed covariates may be plotted on the...

Simulation of realistic censored survival times is challenging. Most research studies use highly simplified models, such as the exponential, that do not adequately reflect the patterns of time to event and censoring seen in real datasets. In this article, I present a general method of simulating...