Those who have been through audits by state tax authorities say the process can be even more intrusive than a visit by the U.S. Internal Revenue Service. The issue is generally whether the person is a resident. And many people don't realize that a citizen can legally be classified as a resident of more than one state.

• A common test for residency is that a person have a permanent place of abode and spend more than 183 days of the year there.

• But tax experts caution that a resident of Connecticut or New Jersey, for example, who has a job in New York and an apartment for occasional use might well be classified as a New York resident -- with even a trip to La Guardia Airport to catch a plane being counted as a New York day.

• Many victims of state tax audits -- including some who have homes in more than one state or who have moved from one state to another -- have found themselves required to dredge through reams of personal and business diaries, credit-card receipts, limousine driver records and telephone invoices to establish one-state residence.

• Until 1996, some states taxed pensions they contended were earned in that state even if the recipients had moved to another state -- but a federal law passed that year ended the practice.

Tax professionals say many honest people have become automatic targets of audits, mainly because they earn high incomes.

Source: Vivian Marino, "An Arduous Audit, and Not by the I.R.S.," New York Times, February 27, 2000.