longitudinal study

The longitudinal study tracked cognitive decline in five thousand adults over a twenty-year period.这项纵向研究追踪了五千名成年人在二十年期间的认知衰退情况。

Longitudinal studies are costly but provide invaluable insight into how outcomes change across the life course.纵向研究成本高昂，但能为结果如何在整个生命历程中发生变化提供无价的见解。