Choose the Research Design That Can Answer the Question

Start with the answer needed

A research design is a plan for obtaining an answer, not a prestige label. First define the population, phenomenon or exposure, intervention when one exists, comparator, outcome, and time frame. Then ask whether the purpose is to describe, explore experience, estimate frequency, test association, estimate an intervention effect, explain a mechanism, or evaluate performance in routine care. A randomized trial can estimate an intervention effect under specified conditions, but it cannot reveal every reason participants find the intervention unacceptable. An interview study can develop that understanding, but it cannot estimate population prevalence from a small purposive sample. The design is strong when its sampling, measurement, comparison, timing, and analysis fit the precise question.