S. Blomquist et V. Christiansen, TOPPING UP OR OPTING OUT - THE OPTIMAL-DESIGN OF PUBLIC PROVISION SCHEMES, International economic review, 39(2), 1998, pp. 399-411
There is extensive public provision of private goods in all developed
countries. The public provision scheme is often designed so that indiv
iduals can opt out, but not top up (supplement) the publicly provided
quantity/quality. Using an optimal income tax/public provision model w
e derive the respective conditions under which a public provision sche
me should allow or forbid supplementing. Disregarding administrative c
osts, a system where individuals are not allowed to top up is optimal
if the demand for the publicly provided good increases in the amount o
f leisure available, while a scheme allowing individuals to top up is
warranted if the demand decreases with the amount of leisure.