BACKGROUND Stepped care is recommended and implemented as a means to organise depression treatment. Compared with alternative systems, it is assumed to achieve equivalent clinical effects and greater efficiency. However, no trials have examined these assumptions. A fully powered trial of stepped care compared with intensive psychological therapy is required but a number of methodological and pr...

An outcome variable is one which we hope to change, predict or estimate in a trial. Examples: • Systolic blood pressure in a hypertension trial • Caesarean section rate in an obstetric trial • Survival time in a cancer trial How many outcome variables should I have? If we have many outcome variables: • all possibilities would be covered, • we would be less likely to miss something, • the risk o...

Clinical trial adaptation refers to any adjustment of the trial protocol after the onset of the trial. The main goal is to make the process of introducing new medical interventions to patients more efficient by reducing the cost and the time associated with evaluating their safety and efficacy. The principal question is how should adaptation be performed so as to minimize the chance of distorti...

BACKGROUND Phase III randomized clinical trials (RCTs) have become larger and are powered to detect small absolute benefits. Temporal changes in absolute benefits of experimental medical therapies reported in RCTs are unknown. METHODS We identified all RCTs with sample size > or =200 evaluating experimental medical therapies for breast and colorectal cancer published from 1975 to 2007. We ass...