What should be described about the population to be studied?

• A. The specific administrative region where the trial will be conducted
• B. The recruitment timeline for the population
• C. Description of the population to be studied
• D. The inclusion and exclusion criteria for the population

Answer: (C)

Defining who will be studied by detailing the population’s characteristics ensures the trial targets the right group and that the results will be applicable to that group. The description should cover key attributes such as the disease or condition being studied, age range, sex, disease stage or severity, geographic location, language, and any other factors relevant to the research question and safety. By outlining these traits, the protocol establishes the scope of the study and guides how participants are identified, recruited, and analyzed, contributing to the study’s validity and generalizability.

Inclusion and exclusion criteria are the specific eligibility rules that operationalize this description, turning the population portrait into concrete enrollment decisions. The region and recruitment timeline are secondary details that don’t define the population’s fundamental characteristics, and while eligibility criteria are essential, the primary requirement is to describe who comprises the population.