A clinical trial is a research study that prospectively assigns health-related interventions to people (or groups) typically using randomisation to evaluate the effects on health outcomes. Well-designed, suitably powered, randomised, trials provide the most reliable evidence about the effectiveness (or not) of interventions and should underpin medical practice. Unfortunately, within paediatrics, many common interventions have not been subjected to such rigorous evaluation,1 ,2 leading to variation in both treatments3 ,4 and outcomes (http://www.rightcare.nhs.uk/index.php/atlas/children-and-young-adults/).

Many more high-quality clinical trials are needed before paediatric care is robustly evidence based. Healthcare professionals are ideally placed to inform such trials, but one factor that limits their involvement is the complexity involved: the processes and requirements for trials of investigational medicinal products are illustrated on the clinical trials route map (http://www.ct-toolkit.ac.uk/routemap).

There has been a significant investment in clinical trials research infrastructure over the last decade recognising this complexity. The UK Clinical Research Collaboration Registered Clinical Trials Units (CTU) Network is part of this infrastructure and oversees the registration of CTUs. Registered CTUs need to demonstrate track record, a multidisciplinary team, robust quality assurance systems, statistical input and secure information technology. CTUs exist to help healthcare professionals navigate this complex landscape and assist in developing clinical questions into well-designed studies.