Equipoise is a state of genuine uncertainty as to which of two treatments is better

Equipoise is a state of genuine uncertainty as to which of two treatments is better. Ethicists consider equipoise to be an ethical requirement for conducting a randomized therapeutic trial: if the researcher is already of the view that one treatment is better than the other, it would be unethical for that researcher to assign patients to the treatment that he or she believes is inferior. Under what conditions can equipoise be achieved in a placebo controlled trial?