In RADAR G3, we ask the parents at three time points (when their child is 3 months, 2 years, and 4.5 years old) to complete an online questionnaire about parenthood, parenting style, and the development of their child. Completing the questionnaire takes between 30 and 45 minutes. When the child is 2.5 years old, a home visit of 1.5 hours takes place. During this home visit, different tasks are conducted with the child to study its development. Also, the parent is asked to participate in some play tasks together with the child. All tasks are recorded with a video camera, so the behavior can be scored by a trained researcher at the university. When the child is 5 years old, the schoolteacher of the child is asked to fill out a short online questionnaire about the behavior of the child in the classroom.