Issues in clinical trials A randomized clinical trial is planned for AIDS patients to investigate whether a new treatment provides improved survival over the current standard treatment. It is not known whether it will be better or worse.

a. Why do researchers use randomization in such experiments rather than letting the subjects choose which treatment they will receive?

b. When patients enrolling in the study are told the purpose of the study, explain why they may be reluctant to be randomly assigned to one of the treatments.

c. If a researcher planning the study thinks the new treatment is likely to be better, explain why he or she may have an ethical dilemma in proceeding with the study.