IcebergSim – a clinical trial simulator, developed by Eduardo Bergel and David Sackett and which can simulate RCTs. A user conceives a trial, including risk subgroups, sample size, outcome rates, effect size, lost to follow-up, compliance, stopping rules, etc. Then the program generates 1000s of such trials. A summary of the results is presented, including relative risks, relative risk reductions, confidence intervals, p-values, etc. A number of graphics is also available. The simulator also includes a sample size calculator for cluster or individually randomised trials. Click here to see.