The inspector general’s report noted the AUR program reviewed 5.6 million tax returns in 2009, only 26 percent of the more than 21.7 million returns flagged for income discrepancies that year. Those returns identified for additional scrutiny were “the cases most likely to produce tax assessments.”

The number of AUR reviews has fallen each year, with 4.2 million of 27.6 million returns identified with income discrepancies — 15.4 percent — getting the more stringent review.

In a July 2011 report, the inspector general’s office recommended the IRS develop procedures to use its AUR system to alert taxpayers as soon as possible when the agency becomes aware their identity has been stolen, and the identity thief has used the information to get a job.

The IRS agreed with the recommendation in that report and said it was “taking corrective actions,” including launching a pilot program in 2014 to “notify a test group of taxpayers that their [Social Security numbers] had been used by another individual for the purpose of battening employment and reporting income.”

The IRS eventually notified 25,000 taxpayers that they were victims of identity theft, but the program was shut down due to a “lack of funding and other competing priorities.”

In his report, McKenney said the IRS does not plan to start a more comprehensive notification program prior to January 2017.

The report also said that due to a lack of an “effective tracking process” for notifying the Social Security administration about cases of employment-related identity theft, those taxpayers’ Social Security benefits may be affected.

In a press release that accompanied the report, Treasury inspector general for tax administration J. Russell George said “employment-related identity theft can cause significant burden to taxpayers, including the incorrect computation of taxes based on income they did not earn.”

Karen Schiller, the IRS’s small business/self-employed division commissioner, agreed with the report’s recommendations and said the IRS takes its obligation to victims of employment-related identify theft seriously.

But Schiller also said the agency needs public support to make its efforts successful.

“Having the public’s help will greatly strengthen and improve our new tools we have to stop the crime of identity theft,” Schiller said.

She pointed out the IRS started a public awareness program in 2015 to help taxpayers learn how to “protect themselves” from identity theft, and will step-up those efforts in advance of the 2016 tax filing season.