TSA does not have valid evidence that most of the indicators in its revised list of behavioral indicators can be used to identify individuals who may pose a threat to aviation security. In our review of all 178 sources TSA cited in support of its revised list, we found that 98 percent (175 of 178) of the sources do not provide valid evidence applicable to the specific indicators that
TSA identified them as supporting. In total, we found that TSA does not have valid evidence to support 28 of its 36 revised behavioral indicators, has one source of valid evidence to support each of 7 indicators, and has 2 sources of valid evidence to support 1 indicator.