A cohort study means you take the same group of people and follow them every five years for that period of time.

定群研究意味着你只有一组研究对象,然后在研究期间每五年进行一次记录数据

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Well, a cross-sectional study would mean that you'd get a random group of the population and measure them in 1970 and then take another random group five years later and measure them, but it wouldn't be the same people necessarily, it would be different groups of people.

那么,横断面研究就是,1970年你在人群中随意选择一组人,并记录下相关数据,然后,五年后再随意选择一组人记录数据,但这不需要是同一组人,通常是不同的人

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选