“…For almost the entire length of the Metropolitan project , data were collected from a range of different registers. The data set includes information on, among other things, income, social welfare recipiency, social group, educational achievement, hospital treatment, interventions from Child Welfare Committees, and involvement in crime (for criminological studies that have used this data set, see, for example, Fry, 1985;Kratzer & Hodgkins 1999;Torstensson, 1987Torstensson, , 1990Wikström, 1987Wikström, , 1990). The other data set, to which the Metropolitan study has been linked, is the Health, Illness, Income and Employment database (the HSIA 1980(the HSIA -2001.…”