Association of Clinical Research Professionals (ACRP) Certified Professional Practice Exam

Which trial design is specifically used for examining interactions of multiple factors?

1. Cohort design

2. Factorial design

3. Cross-over design

4. Sequential design

The correct answer is: Factorial design

Factorial design is specifically used for examining interactions of multiple factors because it allows researchers to systematically evaluate the effects of two or more independent variables simultaneously. In this design, each level of each factor is combined with each level of the other factors, making it possible to observe not only the main effects of each factor but also how they might interact with one another. For instance, if a study investigates the effects of different doses of a medication along with varying levels of physical activity, a factorial design would enable researchers to see not just the effects of the medication and physical activity independently, but also how different doses work in conjunction with different activity levels. This makes factorial design particularly powerful in identifying synergistic effects, potential interactions, and optimizing treatment approaches. Other trial designs do not emphasize the simultaneous examination of multiple factors in this way. Cohort designs typically focus on the incidence of outcomes in groups that share a common characteristic over time. Cross-over designs allow participants to receive multiple treatments in a random order, which can control for participant variability but does not inherently test interactions among multiple factors. Sequential designs are primarily focused on testing treatments one after another, rather than assessing multiple factors simultaneously. Thus, factorial design stands out as the most appropriate for this specific purpose.