Final answer:
The best choice for evaluating the prognosis of a condition over time is a longitudinal study. To evaluate the efficacy of a new screening test, a controlled experiment is typically used. To evaluate the risks and benefits of an intervention, a retrospective or prospective cohort study is often used.
Step-by-step explanation:
The best choice for study designs to evaluate the prognosis of a condition over time is a longitudinal study. This type of study involves following a group of individuals over a period of time to assess the progression of a condition. An example of a longitudinal study is the Cancer Prevention Study-3 (CPS-3), sponsored by the American Cancer Society.
A study design to evaluate the efficacy of a new screening test would typically involve a controlled experiment. This would involve randomly assigning individuals to receive the new screening test or a placebo, and then comparing the outcomes between the two groups.
To evaluate the risks and benefits of an intervention, a retrospective or prospective cohort study is often used. This involves identifying a group of individuals who have been exposed to the intervention and comparing their outcomes with a group of individuals who have not been exposed.