These problems with your tax return could flag the Internal Revenue Service and trigger an audit:

The IRS will contact you if you don’t include Social Security numbers for you and your dependents or other identifying information, plus other data needed to compute your taxes. It probably won’t increase your chances of a real audit unless you cannot or will not comply by coming up with the information the IRS wants.

If you claim credits that require a Taxpayer Identification Number, or TIN, make sure the TIN issuer has the correct number, including the Social Security Administration for any benefits paid you or a dependent. Any discrepancy will raise a flag and cause the IRS to assume the TIN issuer is correct and your return is wrong. The upshot is you can be assessed additional taxes because of the disallowed credits.

The IRS will automatically disallow losses on the sale of your home, surviving spouses who file as married for more than two years; medical deductions for health club dues, funeral expenses or diet foods; itemized deductions for sales taxes, car registration fees and customs duties; personal interest expense write-offs; personal insurance expense deductions.

Make sure you report the exact numbers on your W-2 wage statement and 1099 statements of interest, mutual fund gains, dividends, pensions and so forth. If the statements themselves are wrong, get a corrected copy. Any discrepancy can trigger an audit.

If you’ve been audited before, the IRS will remember. Don’t repeat past mistakes, and do not try to deduct past fines, interest and penalties assessed for past mistakes on your income tax return.