Answer:
longitudinal research
Step-by-step explanation:
A longitudinal survey is an observational study in which data from the same sample are repeatedly collected over an extended period of time, as is the cross-sectional study. This type of research involves following a group of research participants for an extended period of time.
Longitudinal study can take a long time, even decades, depending on the type of data needed to collect. The benefit of the longitudinal study is that researchers can take notes of changes, make observations and detect any changes that occur in the characteristics of their participants and allow a coherent sequence of data to be established.