In Watts, the Federal Circuit ruled that arguments not presented before the Board of Patent Appeals and Interferences could not be raised for the first time on Appeal to the Federal Circuit unless a specific exception applied.  This decision followed existing Federal Circuit precedent regarding Appeals from Federal District Courts to the Federal Circuit.  In addition, the Federal Circuit laid out a test for determining whether errors committed by the Board could be considered harmless errors and thus did not need to be remanded back to the Board even though the Board had technically made an error.