The standard is to have a placebo/control group because then you know for sure if the treatment is responsible for any improvement. Most new treatments either f

The standard is to have a placebo/control group because then you know for sure if the treatment is responsible for any improvement. Most new treatments either fail or provide a small benefit, however if the treatment is found to be extremely effective the trial is stopped and all participants are given access. As you pointed out, it would be unethical to deny access. This happened recently with two Ebola drugs that were being tested during an outbreak.