Randomized Trials or Population-based Registries

New methods introduced for treatment or prophylaxis have to be better, safer, simpler and/or cheaper than the old ones. The new method could derive from pharmacological research, invention of new techniques or observations from registries. Today it is rarely a question of dramatic or all-or-none effects. Therefore, properly designed studies must be performed to show differences in effect. The classical method is the randomized controlled trial...