The IG review comes after hundreds of DHS staff received mandatory reassignments, in some cases to support the Trump administration's immigration crackdown.
FILE - The Homeland Security Department headquarters in northwest Washington, on June 5, 2015. The Department of Homeland Security says the U.S. faces a "heightened threat environment" with the approach of the holidays. (AP Photo/Susan Walsh, File)
Once OPM's final rule takes effect, agencies will have to cap the share of federal employees who can receive high ratings on their performance evaluations.