Beware these 10 common tax filing mistakes.

• Author: Winton, Lisa A.

The AICPA has identified 10 common, avoidable errors made on Federal tax returns that can affect tax liability, delay return processing and, perhaps, draw the IRS's attention:

1. Leaving off attachments: All required schedules and forms should be attached to Form 1040, using the "Attachment Sequence Number" shown in the upper-right-hand corner of each schedule or form. Other statements and schedules can be attached at the end of the return, even if they relate to another form or schedule. The taxpayer's name and Social Security number should be included on every page of each form submitted.

2. Forgetting prior-year carryforwards. Prior-year returns should be checked for any items (e.g., capital losses or charitable deductions) that exceeded the deductible amount and need to be carried forward to the current year.

3. Reporting investment income incorrectly:. Earnings from money market funds are dividends, even though they are often mistakenly reported as interest income.

4. Overpaying Social Security taxes: Taxpayers who worked two or more jobs in 2006 and whose total earnings exceeded $94,200 may have overpaid Social Security taxes. The instructions accompanying Form 1040 explain how to claim a credit.

5. Unnecessarily declaring a state tax refund as income: State tax refunds should not be declared as income on Federal tax returns if the taxpayer did not receive a tax benefit from deducting state taxes. Taxpayers who took the standard deduction in 2005 do not have to include a state tax refund in income for 2006. Taxpayers who were subject to the alternative minimum tax (AMT) in the year the state income taxes were deducted may not have obtained the full benefit of the regular tax deduction for state income taxes; see IRS Pub. 525, Taxable and Nontaxable Income.

6. Failing to document donations: Written acknowledgment from the charity is required to deduct monetary donations of $250 or more. If the gift was property valued at less than $500, the written acknowledgement must describe the property; the taxpayer must file Form 8283, Noncash Charitable Contributions, for properly contributions valued at more than $500. Donations of used clothing and household items after Aug. 17, 2006, must be in "good" or better condition. For 2007, taxpayers have to keep records of all donations by cash or check, showing the details of the contribution. Given that many banks do not return cancelled checks, taxpayers will have to be diligent in getting a detailed...