Many taxpayers are delaying year-end decisions until they see what Washington does with a host of expiring tax measures, including those affecting dividends and capital gains. Yet one of the biggest year-end tax moves is relatively absent from the headlines: whether to convert a traditional Individual Retirement Account to a Roth IRA.

The Roth IRA is partly a play on ­income-tax rates: You contribute to it with after-tax money and don’t owe income tax again. If you expect your personal tax rate to be higher when the money comes out than it was when it went in, it’s a better deal than a traditional IRA, which allows you to defer the tax hit until you make withdrawals in retirement.