Most taxpayers do not understand the difference between credits and deductions and although I'm not a CPA I'll do my best to explain. Credits lower a person's taxes dollar for dollar, making them more valuable than deductions, which merely reduce the amount of income on which taxes are figured. The distinction is critical. A deduction of $1,000 saves $350 in taxes for someone in the highest bracket of 35 percent, but only $100 for someone in the lowest bracket of 10 percent. A credit of $1,000 reduces taxes by that amount, whatever someone's bracket is.
Another difference is that credits come in two flavors, nonrefundable and refundable. Nonrefundable means credits cannot be refunded to the extent that they exceed your income tax. Put another way, credits like the one for child care provide no help after your income tax becomes zero. Refundable means credits like the recently revised one for first-time homebuyers can be refunded to the extent that they exceed your income tax. So even buyers who have no income-tax liability could receive as much as $8,000 from the IRS for the purchase of a home.