You are recruiting patients into a clinical trial of an agent which may reduce the risk of lung cancer among smokers. There are two arms in the study: agent or placebo. You are excited about the trial, as you think the agent has real potential for this purpose. As it happens, you are faced with enrolling a good friend of your mother’s, who remembers your birthday every year and always has a cigarette going. That aspect of the study protocol designed to prevent your personal feelings from influencing the assignment of subjects to groups ln this trial is called:
Group of answer choices
Surveillance bias
Self-selection
Double blind
External validity
