Can the Public's Desire for Future Benefits Be Deduced form Their Private Decisions?

A bstract . How should benefits and costs occurring at different times be evaluated to decide whether to undertake tax financed public projects? What interest rate should be used? If public decisions were based on people's willingness to pay for future private income, they still could not be based on market interest rates. The benefits of public projects (except in the cases of private land values or affected fixed private capital investments) are not marketable. However, among other things, market interest rates do represent the opportunity costs of public investments. Still, many citizens are concerned about the welfare of future generations; they may have a lower time preference rate. Human capital investments are directly analogous to public investment to produce non marketable public goods. Both are illiquid; both yield returns higher than market rates. This indicates the private rates of time preference for most citizens are high.