Following are some particular matters concerning the design and conduct of clinical trials that need to be taken into account when ethical aspects are being considered. Trials should be conducted according to written protocols, which should be approved by Institutional Ethics Committees. The aims of every trial should be precisely stated and important enough to be worth achieving, having in mind the time, effort, cost and possible discomfort that may be involved. The experimental design should be such as to ensure that it will be possible to answer the question asked. In particular institutional ethics committees should be assured of the statistical validity of the design of a proposed trial.
Some trials involve the use of control groups for purposes of comparison.
When informed consent is being sought, costs which may be incurred by subjects as a result of participation in the trial should be discussed with them. There should be a reasonable expectation that the objectives of a clinical trial will be achieved within a defined period of time. In some circumstances it may be unethical to continue a trial for the full period that was planned. For example, it would be wrong to continue if there were substantial deviations from the trial protocol, or if side effects of unexpected type or frequency were encountered. The progress of a trial should generally, therefore, be monitored.