Answer:longitudinal study.
Explanation:According to psychology, a longitudinal study evaluate how participants undergo changes over a period of time.
The prevalent method used is prospective study. It focuses on starting with the people of the same age or people who start to receive a particular medical treatment at the same time.
Longitudinal studies uses the cohort , cohort refers to either people of the same age or who engage in the same activity at the same time.
There are two types of longitudinal design:
- Retrospective looks at how people ended with the same situation and what might have led to that so it observes historical cases.
- Prospective studies looks at the future at tries to track the progress of individuals who started the same thing at the same time and see if they are differences in the future