The U.S. Supreme Court left in place a divide over how to raise a valid False Claims Act lawsuit when it denied review of an education fraud case ruling April 1.

Passing on an opportunity to provide clarity on Justice Clarence Thomas’s 2016 opinion leaves appeals courts to apply different standards for what a complaint must say to adequately allege falsity in fraud cases against contractors and other defendants.

The 2016 ruling, Universal Health Servs., Inc. v. United States ex rel. Escobar, adopted the implied certification theory of liability under the FCA.

Under this theory, contractors who request payments...