Rapid changes in society over recent years, particularly the increasing number of families in which both partners work in the labour market, have led to changes in family structures in Australia. Women's labour force participation has been on the increase since the 1960s. Even when employed women reduce their domestic labour considerably, especially if they are employed for more than 30 hours per week they still do more household work than men. The household work contradictions involved can be illustrated from discrepancies within and between macro institutional and micro interaction orders that cause problems for three-job families. Researchers have also focused on sex role attitudes and their effect on the household division of labour. They have attempted to measure sex role attitudes using structured questionnaires on men's and women's gender roles and role reversal. The overseas and Australian literature on the quantification of household task performance indicates inequalities of task performance between men and women, even when women are employed.