Clinical Study Design - Other Terms

Other Terms

• The term retrospective study is sometimes used as another term for a case-control study. This use of the term "retrospective study" is misleading, however, and should be avoided because other research designs besides case-control studies are also retrospective in orientation.
• Superiority trials are designed to demonstrate that one treatment is more effective than another.
• Non-inferiority trials are designed to demonstrate that a treatment is at least not appreciably worse than another.
• Equivalence trials are designed to demonstrate that one treatment is as effective as another.
• When using "parallel groups", each patient receives one treatment; in a "crossover study", each patient receives several treatments.
• A longitudinal study assesses research subjects over two or more points in time; by contrast, a cross-sectional study assesses research subjects at one point in time.