Certified Clinical Research Associate (CCRA) Practice Exam 2025 – All-in-One Guide to Master Your Certification!

A factorial design in a clinical trial is best described by examining multiple interventions simultaneously. This type of design allows researchers to study the effects of two or more independent variables (factors) and their interactions on a dependent variable. For instance, in a factorial design, participants might be assigned to different combinations of treatments, which enables the assessment of both individual treatment effects and the interaction effects between the treatments.

This approach is particularly efficient because it can provide insights into how various interventions may work together or how their effects differ when applied in combination, which would not be possible in designs focused on single interventions. By examining multiple factors simultaneously, researchers can gather more comprehensive data while using fewer participants than would be required if each possible combination were studied separately.

In contrast, designs focused on only one intervention, comparing two parallel groups, or reviewing historical data do not capture the multi-faceted nature of interventions that factorial designs allow, making option B the most representative of factorial design principles in clinical research.