This research develops a general framework to analyse how taxpayers are likely to respond to a market that supplies a variety of schemes for reducing tax liabilities. These schemes differ in their legal effectiveness and hence in the risks to which they expose taxpayers. The framework is used to explore the impact of a range of four generic anti-avoidance policies: disclosure, penalties, policy design, and the introduction of GAARs or mini-GAARs that give greater clarity about how different types of scheme will be treated. The theoretical model shows how these different policies affect both the use of schemes overall, and how taxpayers choose between different types of scheme. The first three policies deter taxpayers from using schemes generally, but differ in how they induce tax payers to switch between different types of scheme. The fourth produces mixed deterrence effects.