What are the survey units and reporting units for the survey of college students' health status?

The survey unit of college students' health status survey is each student, and the reporting unit is the school. The investigation unit is the specific individual of the investigation object, and there is a difference between the investigation unit and the reporting unit. Investigation units can be individuals, enterprises and institutions, or things. According to different investigation purposes, the investigation unit and the reporting unit are sometimes consistent and sometimes inconsistent.