Generally, randomized studies are designed to evaluate an intervention by comparing it to at least one other intervention or a control group. They are considered to be the most scientifically rigorous methodology to address questions of causation. However, in humanitarian and disaster settings, the use of randomized studies has been questioned by some people. Up to half of the participants in a randomized study will receive no intervention or a placebo (which contains no active ingredient). One intervention might be compared with another intervention of known effectiveness to determine which is more effective. As the severity of an emergency or disaster increases, the burdens and risks associated with randomized trials can increase. It must always be asked whether these trials should be conducted during the disaster.
Another concern is whether giving anyone with a serious illness a placebo is ethical, thinking is it not better to give them something? But when that something is an intervention of unknown benefits and risks, a placebo might be the safer option. If an invention of some effectiveness is available, that should be given to the control group instead of a placebo. The various risks in a randomized trial can be offset with various technical mechanisms, for example, by conducting frequent interim analyses, picking randomization methods that address ethical concerns best, and taking into account the needs of the affected population. Ultimately, the benefit of rigorous evidence production from randomized trials will lead to improved interventions, increased social trust, and thereby reduced harms from disasters.
Other ethical and practical challenges should also be addressed at the individual participant or community level. For example, explaining randomization can be challenging as it may unintentionally feel like discrimination. Some cultures or languages may not have the words to describe scientific randomization, which can present challenges during recruitment and consent. In cases where it is unethical to withhold an intervention from an affected population, alternative designs should be considered. Various innovative designs are being developed regularly, like stepped wedge or adaptive design.