Come spring, U.S. Census workers will be knocking on doors to gather information from those folks who did not return questionnaires by the April 9, 2010 deadline. But before you open your door, please make sure the person knocking is the real deal by showing his or her government identification card.

To protect yourself from census fraud:

Verify the identity of anyone posing as a census employee: they should have government-issued identification. The person must present an ID badge which contains a Department of Commerce watermark, an expiration date and, depending on their function, a photograph; will provide you with supervisor contact information and/or the regional office phone number for verification, if asked; will provide you with a letter from the director of the Census Bureau on U.S. Census Bureau letterhead; may be carrying a laptop and/or bag with a Census Bureau logo. Never give out Social Security numbers or bank account, credit card, or other financial information.

Take your time in responding to census questionnaires that arrive in the mail, to verify their legitimacy. Official questionnaires will never ask for personal financial information or charge a fee.

Don't answer questions if callers ask for a donation; they're not from the Census Bureau.

Sources: AARP and the U.S. Census Bureau