What are randomised control trials?

• Randomised controlled trials (RCT) are a specific type (design) of research study
• RCTs are used to test whether treatments are effective or not
• RCTs are used where there is uncertainty about the balance of risks and benefits for a particular treatment.
• If well designed and executed they provide the most reliable evidence about whether a treatment is effective or not
• High quality RCTs including large numbers of patients (often 1000s) will provide more reliable evidence than RCTs including smaller numbers
• RCTs may be used to test the effectiveness of medicines (e.g. aspirin), therapies (e.g. physiotherapy), devices (e.g. anti-embolism stockings), services (e.g. stroke units)