Sunday, November 7, 2004; Page F03

• In economic policy, the taxation of personal income only when it is spent on goods and services (see also Consumption-Based Income Tax).

• An income tax that essentially would allow people to contribute unlimited amounts of money to individual retirement accounts, to be taxed only when withdrawn.

• A concept first proposed by David F. Bradford, a Treasury official in the Ford administration and later championed by former senator Sam Nunn and Sen. Pete V. Domenici (R-N.M.)

• According to many economists, a tax system that could boost long-term economic growth by encouraging more savings and investment.

• According to liberal critics, the functional equivalent of a national sales tax that favors the wealthy by delaying or eliminating taxation of investment income.

• An idea likely to resurface as part of the still-undefined Bush tax reform and simplification effort.

-- S.P.