The ARB recently ruled that an employer advancing an after-acquired evidence defense in an AIR 21 whistleblower case must prove the defense by clear and convincing evidence.  Clemmons v. Ameristar Airways, Inc., ARB No. 12-105, ALJ No. 2004-AIR-011 (ARB Nov. 25, 2013).  This is the same standard that applies to an employer’s burden of showing, if and when an employee establishes a prima facie case, that it would have made the termination decision regardless of the protected activity.