A huge study took place in Denmark from 1971 until 1997. It tracked all individuals born in this time period, and their moves across municipal boundaries, from birth until age 14, and gathered just under 1.5 million data points! Perhaps as expected, moves in this time were seen to increase all negative outcomes of interest: attempted suicide, violent criminality, psychiatric illness, substance misuse, and natural and unnatural deaths. The risks of these outcomes were increased with the increasing age of children when the move occurred, and they also increased with an increasing number of moves. There was no difference with regards to the class of the family, and largely no difference due to gender of the children. This data points to the seriousness of issues that may occur when children are moved during key developmental periods, largely due to disruptions to children’s schooling, social relationships, and development.