While their names are public record, their duties as the "art tax police" for Uncle Sam are done behind closed doors. Select art world figures who volunteer from the auction, gallery and museum spheres gather twice a year to review taxes on artwork valued at over $50,000. They are called the Art Advisory Panel of the Commissioner of Internal Revenue.

They consider and debate if values from estate executors (who lean toward lower values to pay lower taxes) or museum donors (who lean toward higher values for tax deductions) are accurate or not. About half the time, the panel goes against the taxpayer.

The panel investigated 444 works last year for an aggregate total of $348 million, or an average of $784,000 per piece. It raised the values of 171 artworks in estates by two-thirds.

Usually, the IRS goes along with the panel's recommendations.

The Wall Street Journal reports that the panel can also issue an advance ruling for a museum donation before the donor deducts it from taxes. The cost, as allowed by the IRS, is $2,500.