A TSA security officer watches as passengers go through security at the Salt Lake City International Airport, Nov. 21, 2012. (GEORGE FREY/REUTERS)

A federal review concludes there’s no solid evidence that airport checkpoint personnel have a clue when they scan the approaching line for suspicious passengers.

In a report to be presented to a House subcommittee Thursday, the Government Accountability Office says there is no evidence that it’s effective for Transportation Security Administration officers to scan crowds for telltale signs someone might be a terrorist.

Critics have suggested that the stress and exhaustion that often accompany air travel are too easily misread as suspicious behavior.

The GAO report recommends that Congress stop funding for the program, which has cost more than $878 million since its launch in 2007.

TSA Administrator John S. Pistole is scheduled to join the GAO’s Stephen M. Lord in testimony before the committee Thursday. While the program predates Pistole’s appointment to head the agency, its mission is consistent with his drive toward a risk-based system rather than one in which all passengers receive the same treatment, regardless of the risk they appear to pose.

Rep. Richard Hudson (R-N.C.), chairman of the subcommittee on transportation security, called the hearing “a timely opportunity to review whether this program and others are an effective and efficient use of resources.”

Rep. Bennie Thompson (Miss.), the top-ranking Democrat on the Committee on Homeland Security, said the GAO report confirmed that the program “is fundamentally flawed, cannot be proven effective, and should no longer be funded with taxpayer dollars.”

The TSA defended the program Wednesday.

“Behavior detection is vital to TSA’s layered approach to deter, detect, and disrupt individuals who pose a threat to aviation,” the TSA said in statement responding to the report. “Looking for suspicious behavior is a common sense approach used by law enforcement and security personnel across the country and the world.”

The Screening of Passengers by Observation Techniques (SPOT) program employs 2,800 TSA personnel.

“TSA has not demonstrated that [behavior-detection officers] can consistently interpret the SPOT behavioral indicators,” the GAO report says. “The subjectivity of the SPOT behavioral indicators and variation in BDO referral rates raise questions about the continued use of behavior indicators for detecting passengers who might pose a risk to aviation security.”

The GAO recommends that funding be “directed to programs that have demonstrated their effectiveness.”

“We completely support defunding it,” said Maya Berry, executive director of the Arab American Institute, who wrote to Homeland Security Secretary Janet Napolitano in June urging an end to SPOT.

“It’s discriminatory in nature and terribly ineffective,” Berry said. “It’s used to target people who are perceived to be Arab Americans. We have a deep history and understanding of how this program works, and that is related to experience that Americans of Arab descent have when they travel to Israel.”

The watchdog group Judicial Watch, which has criticized the TSA and Department of Homeland Security as virtually dysfunctional, agreed with the GAO recommendation.

“The TSA continues to treat all fliers as a potential threat,” said Tom Fitton, president of Judicial Watch. “They’re just looking at behavior and not looking into other things, like travel patterns. They’re not focused on what they ought to be focused on.”

Behavior-detection officers work in pairs at airport checkpoints, using an evaluation system of behaviors that suggest that someone should be scrutinized. The TSA workers may ask a police officer to talk with the passenger. If that doesn’t resolve the concerns, the person may not be permitted to pass through to the boarding area.

During a one-year period ending in September 2012, TSA records show that 37,370 passengers were targeted under the SPOT program, 2,214 were referred to a police officer and 199 were arrested. The TSA screens about 1.8 million passengers a day at 450 U.S. airports.

Rep. Cedric L. Richmond (La.), the top-ranking Democrat on the subcommittee, called the GAO report “a serious indictment” of the SPOT program.

“With a single report, GAO has displayed that the science behind the program is nonexistent and that the study TSA cites in defending the program was fundamentally flawed,” Richmond said. “Given TSA’s unwillingness to concur with GAO’s recommendation that the agency limit funding for the program until it could be proven, it is now up to Congress to take a hard look at reprioritizing the funding for this program.”