Randomized clinical trials: problems and values.

Problems with randomization can be grouped as ethical or methodological. Those who consider randomization unethical believe it deprives patients of their best chance for a good result or actually does them harm. Methodological criticisms are based on the selectivity of randomized studies in terms of time and money. Finally, although no one suggests that randomization produces any statistical disadvantage, some critics think that its statistical advantages have been exaggerated.