Is Basic Income more expensive because it creates work incentives at the bottom ?

Marginal rates at the bottom and in the middle: the big trade off. To be fair, however, the fact that the basic income is not means-tested naturally combines with the mild requirement that the explicit rate of tax should fall short of 100%. Which means that the sort of basic income proposal we should be looking at is not represented by Figure 2, but rather by Figure 4, or at least by Figure 6. [Figures 1, 4, 6] Relative to the conventional guaranteed minimum scheme represented by Figure 1, it can then no longer be said that there is not genuinely higher cost. True, it does not uniquely stick to the universal nature of the benefit, since the corresponding means-tested negative-income-tax variants share exactly the same feature. In particular, a linear tax combined with a uniform refundable tax credit at the current level of the minimum guaranteed income would be very expensive in this sense. [Fig. 3] But that the problem should be entirely shared with negative income schemes does not make it less of a problem, which needs to be faced squarely. The basic fact is that the more material incentives one wishes to provide (for a given minimum income) to people earning at the bottom of the earnings scale, the more one needs to decrease the material incentives higher up. There is a sharp trade off here. [Cf.Example]