The Family Assistance Plan and the President's Commission on Income Maintenance Programs are both proposals which incorporate a negative income tax provision and which are aimed at reforming the present welfare system. This study is concerned with the effect these proposed income supplements will have on work decisions of male heads of families in New York City. More specifically, data from the 1967 Survey of Economic Opportunity and information concerning the labor market and family incomes were used to estimate the likely impact of these programs on work decisions, the costs of the programs, and whether there should be voluntary state or local supplementation of federal payments. Findings of the study include: (1) There is evidence indicating that the hours of work of male heads of families in New York City are more responsive to changes in economic incentives than the hours of work of male family heads in the rest of the nation, and (2) If the Family Assistance Plan is enacted, there will be an appreciable reduction in the supply of low-wage male labor. (JS)