Extending the Yale Law School dominance of academic theories of the income tax exemption in a 1990 article Professor Rob Atkinson a Yale graduate and former student of Professor Hansmann defended exemption as a proper government encouragement of altruism in society. Criticizing Hansmann's theory as too narrow and economically driven, Atkinson theorized that all nonprofit organizations other than "mutual commercial nonprofits" are valued for the very reason of their nonprofit status. Another possible justification for exempting all nonprofits exists in t another variation on the community benefit theme. Refer to this as the "public trust" variant. One might overcome the central flaw in Atkinson's position by arguing that nonprofits are deterred or hindered by virtue of state law provisions that impose more stringent organizational and operational constraints on nonprofit than for-profit enterprises. The most important criterion is deservedness, which has two distinct components: whether the theory identifies activities that are both worthy of and in need of a social subsidy.