Dona is a graduate student investigating the development of fine motor skills. She selects a group of children and assesses their fine motor skills every six months over a two-year period. In this example, Dona is using a research method.

The correct answer is longitudinal

Research data can be related to time in two ways: In the first, all variables refer to a single period, time is constant, this is the transversal method. In the second, the variables can refer to different moments, the time is now variable, and the method is now classified as longitudinal.

In longitudinal methods, time is variable. It can be just a before and after, hourly intervals throughout the day, months throughout the year, years over decades ... what matters is that there is more than one moment, more than one period.