1. Randomised placebo and drug administration is more likely to accurately reflect the effects of the drug than the nonrandomised, non-placebo controlled methods used in earlier studies. 2. Randomised placebo and drug administration limits the chances of introducing bias into the study by eliminating selection bias. 3. Randomised placebo and drug administration also helps to control for outside factors which could influence the results, such as diet or lifestyle. 4. Randomised placebo and drug administration minimises the risk of the study being misinterpreted due to the placebo effect or other factors. 5. Randomised placebo and drug administration helps to ensure that the results can be compared to other studies and are widely accepted as valid.