Keep these simple rules in mind:

• No one from the IRS or the Census bureau will ever email you about your taxes or the Census. Ever.
• No one from the IRS or the Census bureau will call you and ask for your address, social security number, and bank account information. Ever.
• No one from the IRS or the Census bureau will ask for money, a donation, passwords, or pin numbers over the phone or via email. Ever.

If you get a phone call from the IRS and do not feel comfortable with the questions they ask to identify you, the real IRS is always willing to accept a callback. Their phone number is 1-800-829-1040 (800-TAX-1040). Doing this callback will (almost) always ensure you are talking to the IRS.

This is a good rule of thumb for any unsolicited phone call. If the questioning or “verification process” makes you feel uncomfortable or involves revealing sensitive information such as a mother’s maiden name, social security number, driver’s license number, bank information, or credit information, get a callback name and number. Anyone can spoof an outgoing phone number, so caller id is no protection here. In the case of official agencies, it’s fairly easy to verify the listed phone number before making the callback, and legitimate businesses will never try to goad you into giving information.

If you are struggling with confrontation, all legitimate businesses will also be willing to conduct business via mail. Specifically in cases of debt collection or IRS matters, request the correspondence be provided via US mail instead of the telephone. Legitimate agencies will comply with this request, anyone who doesn’t you can safely hang up on.

Further Reading:
Census on Scams
IRS on Scams