funding is not economically desirable. most international systems of social insurance are funded on an ongoing basis without reference to future liabilities. that is seen as a matter of solidarity between generations and between the sick and the healthy as a part of the social contract. the current generation of healthy working people pay something now to meet the health care and living costs of those who are currently temporarily incapacitated through sickness or who have ceased work through old age or disability. the main exception is in the united states, where the two largest programs, medicare and social security programs, the administrators have historically collected more in social premiums than they have paid out as social benefits. the difference is retained in a trust fund. in both programs, us government actuaries periodically attempt to predict up to 70 years in advance the longevity of the fund and must estimate the future rates of contributions and pensions, the types of health care needs of the beneficiaries, and what that might cost. no other country in the world does so. despite the us programs being in considerable surplus, the political argument is often that these programs are "going bankrupt" or that politicians have spent the money on other things. welfare welfare is a large program of social insurance that creates many externalities. with welfare, the beneficiary's contributions to the program are taken into account. a welfare program pays recipients based on need, not contributions. in the us, there are welfare-to-work programs that give unemployed people an incentive to work if they are starting to seek a job. the people who use these programs are government expenditures and are closely monitored to make sure that they are searching for a job. they will receive several benefits once they find a job including wage subsidies and tax breaks. welfare-to-work programs like these try to give people the incentive to work because, without them, people have a strong incentive to stay unemployed.