Follow-up Study
A follow-up study is a data collection method, which enables you to produce knowledge on the chosen phenomenon regularly and repetitively over a particular period of time.
You can carry out this type of data collection in several ways, for example, by either observing or interviewing the focus group. This form of data collection may also be electronic if the researched phenomenon is accessible through the Internet. Digital communication has opened up various new possibilities to carry out follow-up studies.
Read more on follow-ups from the links below:
Longitudinal study. Wikipedia, The Free Encyclopedia.
Cho. Longitudinal Research. Web Center for Social Research Methods.