On the other hand, with an estate tax, a greater amount of wealth has to be accumulated to leave a given after-tax bequest, so the tax might induce the individual to work harder to maintain the net value of his estate. Consequently, the effect of an estate tax on a donor’s effort is logically indeterminate. Similarly, one cannot predict how the tax will affect the amount of savings. There is currently very little in the way of empirical evidence on these incentive issues.