追踪调查
zhuī​zōng​diào​chá

follow-up study

追踪调查 (追蹤調查) zhuī​zōng​diào​chá
follow-up study
A longitudinal research method involving repeated observations of subjects over an extended period.
tracking investigation
The process of following leads or monitoring a subject as part of an ongoing investigation.

Sources
Definitions
CC-CEDICT