Filing Time Doesn't Affect Tax Audits / The IRS won't single you out for filing an extension

• TOM HERMAN for the Wall St. Journal writes:  
Question: If I got an extension to file my federal income-tax return and file it before the Oct. 15 deadline, is that likely to make a difference in my chances of getting audited compared to filing by the April 15 deadline?

Answer: No, replies a spokesman for the Internal Revenue Service. "Extensions have no impact on your chances of being audited," he says.

Several private-sector tax experts agree. "In my experience, the simple answer to your reader's question is that filing in April or October does not affect the chances of being 'audited,' " says David A. Lifson, a certified public accountant at Crowe Horwath LLP in New York.

Just be sure to file on time. "I have also noticed that filing a tax return late almost always attracts extra attention," he says. "So I wouldn't consider missing the Oct. 15 extended due date."

The IRS typically audits about 1% of all the individual returns it receives each year. There are several different types of audits. Most are "correspondence" audits, done by mail. Typically, these occur when you report something on your return that differs from what the IRS has received from employers, investment firms and other sources.

In these cases, you would be instructed to send supporting documents to the IRS, says Stephen W. DeFilippis of DeFilippis Financial Group in Wheaton, Ill.

"If your return contains something that would trigger the IRS matching program 'correspondence audit,' I don't believe it matters when you file," says Mr. DeFilippis, who is an enrolled agent, a tax expert authorized to represent taxpayers at all levels of the IRS. "The computer will pick up on the mismatch whether you file in February or October."

Many other factors can lead to an audit. For example, as the IRS says, your return may be selected on the basis of "computer scoring." The IRS scores returns based on a secret formula designed to spot those where "the potential is high that examination of your return will result in a change to your income tax liability."