Itemized deductions are permitted for expenditures on particular goods and services. They are phased out at high-income levels. Itemized deductions change after-tax relative prices, which often affects economic behavior.

• 特定商品和服务的支出可以分项扣除,并在高所得水平上逐步减少。分项扣除改变税后相对价格,这常常影响经济行为。