In a trial protocol, which elements must be explicitly defined as the primary and secondary outcomes to be measured?

• A. Adverse Events Only
• B. Primary and Secondary Endpoints
• C. Recruitment Targets
• D. Sponsor Name

Answer: (B)

In a trial protocol, the outcomes that will be used to assess the study’s objectives must be clearly defined as the primary and secondary endpoints. The primary endpoint is the main result the trial is designed to evaluate and directly addresses the primary objective; secondary endpoints are additional outcomes that provide more information about effects or safety. Defining them explicitly before data collection ensures the study stays unbiased, guides the sample size calculation, and specifies exactly how and when each outcome will be measured, what instruments or scales will be used, and which analysis population will be analyzed. Safety-related information, such as adverse events, is important and may be included as safety endpoints or secondary endpoints, but the essential requirement is that the primary and secondary outcomes—the specific measures to be recorded and analyzed—are predefined. Recruitment targets and sponsor name are not about the outcomes to be measured.