Which outcome is a disadvantage of a longitudinal research design?

A) Individuals of different ages are being compared to one another.
B) Longitudinal samples cannot be representative of the overall population.
C) Longitudinal studies fail to track changes over time.
D) Research participants may drop out due to moving, loss of interest, or death.

Longitudinal

An observational research method in which data is gathered for the same subjects repeatedly over a period of time.

Participants

Participants are individuals who take part in a process or activity, especially in research or experiments.

Representative

Serving as a typical or characteristic example of a group or class; or, in politics, someone elected to act and speak on behalf of a wider group.