The purpose of this survey was to ascertain answers to such questions as whether societies are becoming more or less equal, whether they are expanding or restricting opportunity for their citizens and whether they are offering the kinds of education that will enable nations to cope with the challenges of technological change. The aim was to study the trends, correlates and determinants of social mobility in Northern Ireland and the Irish Republic. The researchers state that they would welcome requests for access to these data. (This dataset contains information about initial contact only). Males aged 18 - 64 living in household since 15 September 1972 who are not on electoral register, males aged 18 - 64 moved to household since 15 September 1972, number of persons in household (ages).